diff --git a/services/document-updater/.mocharc.json b/services/document-updater/.mocharc.json
new file mode 100644
index 0000000000..dc3280aa96
--- /dev/null
+++ b/services/document-updater/.mocharc.json
@@ -0,0 +1,3 @@
+{
+  "require": "test/setup.js"
+}
diff --git a/services/document-updater/.nvmrc b/services/document-updater/.nvmrc
index 2baa2d433a..e68b860383 100644
--- a/services/document-updater/.nvmrc
+++ b/services/document-updater/.nvmrc
@@ -1 +1 @@
-10.23.1
+12.21.0
diff --git a/services/document-updater/Dockerfile b/services/document-updater/Dockerfile
index 2da67d2436..4f417a2a4b 100644
--- a/services/document-updater/Dockerfile
+++ b/services/document-updater/Dockerfile
@@ -2,7 +2,7 @@
 # Instead run bin/update_build_scripts from
 # https://github.com/sharelatex/sharelatex-dev-environment
 
-FROM node:10.23.1 as base
+FROM node:12.21.0 as base
 
 WORKDIR /app
 
diff --git a/services/document-updater/Makefile b/services/document-updater/Makefile
index 596aa47fdb..7591d2a689 100644
--- a/services/document-updater/Makefile
+++ b/services/document-updater/Makefile
@@ -21,8 +21,10 @@ DOCKER_COMPOSE_TEST_UNIT = \
 	COMPOSE_PROJECT_NAME=test_unit_$(BUILD_DIR_NAME) $(DOCKER_COMPOSE)
 
 clean:
-	docker rmi ci/$(PROJECT_NAME):$(BRANCH_NAME)-$(BUILD_NUMBER)
-	docker rmi gcr.io/overleaf-ops/$(PROJECT_NAME):$(BRANCH_NAME)-$(BUILD_NUMBER)
+	-docker rmi ci/$(PROJECT_NAME):$(BRANCH_NAME)-$(BUILD_NUMBER)
+	-docker rmi gcr.io/overleaf-ops/$(PROJECT_NAME):$(BRANCH_NAME)-$(BUILD_NUMBER)
+	-$(DOCKER_COMPOSE_TEST_UNIT) down --rmi local
+	-$(DOCKER_COMPOSE_TEST_ACCEPTANCE) down --rmi local
 
 format:
 	$(DOCKER_COMPOSE) run --rm test_unit npm run --silent format
diff --git a/services/document-updater/app/js/RangesTracker.js b/services/document-updater/app/js/RangesTracker.js
index 6107acf300..5991ee2993 100644
--- a/services/document-updater/app/js/RangesTracker.js
+++ b/services/document-updater/app/js/RangesTracker.js
@@ -706,8 +706,10 @@ const load = function () {
           return result
         } else if (c1.op.i != null && c2.op.d != null) {
           return 1
-        } else {
+        } else if (c1.op.d != null && c2.op.i != null) {
           return -1
+        } else {
+          return 0
         }
       })
 
@@ -728,8 +730,10 @@ const load = function () {
           return result
         } else if (a.i != null && b.d != null) {
           return 1
-        } else {
+        } else if (a.d != null && b.i != null) {
           return -1
+        } else {
+          return 0
         }
       })
 
diff --git a/services/document-updater/buildscript.txt b/services/document-updater/buildscript.txt
index 0d8b15d9f5..2d2f00495e 100644
--- a/services/document-updater/buildscript.txt
+++ b/services/document-updater/buildscript.txt
@@ -3,6 +3,6 @@ document-updater
 --docker-repos=gcr.io/overleaf-ops
 --env-add=
 --env-pass-through=
---node-version=10.23.1
+--node-version=12.21.0
 --public-repo=True
---script-version=3.4.0
+--script-version=3.7.0
diff --git a/services/document-updater/docker-compose.yml b/services/document-updater/docker-compose.yml
index 0db448f9b5..6a1c097a30 100644
--- a/services/document-updater/docker-compose.yml
+++ b/services/document-updater/docker-compose.yml
@@ -6,7 +6,7 @@ version: "2.3"
 
 services:
   test_unit:
-    image: node:10.23.1
+    image: node:12.21.0
     volumes:
       - .:/app
     working_dir: /app
@@ -18,7 +18,7 @@ services:
     user: node
 
   test_acceptance:
-    image: node:10.23.1
+    image: node:12.21.0
     volumes:
       - .:/app
     working_dir: /app
diff --git a/services/document-updater/package-lock.json b/services/document-updater/package-lock.json
index ac530644db..65b0a0d9c2 100644
--- a/services/document-updater/package-lock.json
+++ b/services/document-updater/package-lock.json
@@ -819,6 +819,12 @@
         }
       }
     },
+    "@ungap/promise-all-settled": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/@ungap/promise-all-settled/-/promise-all-settled-1.1.2.tgz",
+      "integrity": "sha512-sL/cEvJWAnClXw0wHk85/2L0G6Sj8UB0Ctc1TEMbKSsmpRosqhwj9gWgFRZSrBr2f9tiXISwNhCPmlfqUqyb9Q==",
+      "dev": true
+    },
     "abbrev": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/abbrev/-/abbrev-1.1.1.tgz",
@@ -887,6 +893,12 @@
         "uri-js": "^4.2.2"
       }
     },
+    "ansi-colors": {
+      "version": "4.1.1",
+      "resolved": "https://registry.npmjs.org/ansi-colors/-/ansi-colors-4.1.1.tgz",
+      "integrity": "sha512-JoX0apGbHaUJBNl6yF+p6JAFYZ666/hhCGKN5t9QFjbJQKUU/g8MNbFDbvfrgKXvI1QpZplPOnwIo99lX/AAmA==",
+      "dev": true
+    },
     "ansi-escapes": {
       "version": "4.3.1",
       "resolved": "https://registry.npmjs.org/ansi-escapes/-/ansi-escapes-4.3.1.tgz",
@@ -919,6 +931,16 @@
         "color-convert": "^1.9.0"
       }
     },
+    "anymatch": {
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/anymatch/-/anymatch-3.1.1.tgz",
+      "integrity": "sha512-mM8522psRCqzV+6LhomX5wgp25YVibjh8Wj23I5RPkPppSVSjyKD2A2mBJmWGa+KN7f2D6LNh9jkBCeyLktzjg==",
+      "dev": true,
+      "requires": {
+        "normalize-path": "^3.0.0",
+        "picomatch": "^2.0.4"
+      }
+    },
     "aproba": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/aproba/-/aproba-1.2.0.tgz",
@@ -1112,6 +1134,12 @@
       "resolved": "https://registry.npmjs.org/bignumber.js/-/bignumber.js-7.2.1.tgz",
       "integrity": "sha1-gMBIdZ2CaACAfEv9Uh5Q7bulel8="
     },
+    "binary-extensions": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/binary-extensions/-/binary-extensions-2.2.0.tgz",
+      "integrity": "sha512-jDctJ/IVQbZoJykoeHbhXpOlNBqGNcwXJKJog42E5HDPUwQTSdjCHdihjj0DlnheQ7blbT6dHOafNAiS8ooQKA==",
+      "dev": true
+    },
     "bindings": {
       "version": "1.5.0",
       "resolved": "https://registry.npmjs.org/bindings/-/bindings-1.5.0.tgz",
@@ -1182,10 +1210,19 @@
         "concat-map": "0.0.1"
       }
     },
+    "braces": {
+      "version": "3.0.2",
+      "resolved": "https://registry.npmjs.org/braces/-/braces-3.0.2.tgz",
+      "integrity": "sha512-b8um+L1RzM3WDSzvhm6gIz1yfTbBt6YTlcEKAvsmqCZZFw46z626lVj9j1yEPW33H5H+lBQpZMP1k8l+78Ha0A==",
+      "dev": true,
+      "requires": {
+        "fill-range": "^7.0.1"
+      }
+    },
     "browser-stdout": {
       "version": "1.3.1",
       "resolved": "https://registry.npmjs.org/browser-stdout/-/browser-stdout-1.3.1.tgz",
-      "integrity": "sha1-uqVZ7hTO1zRSIputcyZGfGH6vWA=",
+      "integrity": "sha512-qhAVI1+Av2X7qelOfAIYwXONood6XlZE/fXaBSmW/T5SzLAmCgzi+eiWE7fUvbHaeNBQH13UftjpXxsfLkMpgw==",
       "dev": true
     },
     "bson": {
@@ -1269,12 +1306,6 @@
         "type-detect": "^1.0.0"
       }
     },
-    "chai-spies": {
-      "version": "0.7.1",
-      "resolved": "https://registry.npmjs.org/chai-spies/-/chai-spies-0.7.1.tgz",
-      "integrity": "sha1-ND2Z9RJEIS6LF+ZLk5lv97LCqbE=",
-      "dev": true
-    },
     "chalk": {
       "version": "2.4.2",
       "resolved": "https://registry.npmjs.org/chalk/-/chalk-2.4.2.tgz",
@@ -1292,6 +1323,22 @@
       "integrity": "sha512-mT8iDcrh03qDGRRmoA2hmBJnxpllMR+0/0qlzjqZES6NdiWDcZkCNAk4rPFZ9Q85r27unkiNNg8ZOiwZXBHwcA==",
       "dev": true
     },
+    "chokidar": {
+      "version": "3.5.1",
+      "resolved": "https://registry.npmjs.org/chokidar/-/chokidar-3.5.1.tgz",
+      "integrity": "sha512-9+s+Od+W0VJJzawDma/gvBNQqkTiqYTWLuZoyAsivsI4AaWTCzHG06/TMjsf1cYe9Cb97UCEhjz7HvnPk2p/tw==",
+      "dev": true,
+      "requires": {
+        "anymatch": "~3.1.1",
+        "braces": "~3.0.2",
+        "fsevents": "~2.3.1",
+        "glob-parent": "~5.1.0",
+        "is-binary-path": "~2.1.0",
+        "is-glob": "~4.0.1",
+        "normalize-path": "~3.0.0",
+        "readdirp": "~3.5.0"
+      }
+    },
     "chownr": {
       "version": "1.1.4",
       "resolved": "https://registry.npmjs.org/chownr/-/chownr-1.1.4.tgz",
@@ -1333,6 +1380,12 @@
       "resolved": "https://registry.npmjs.org/code-point-at/-/code-point-at-1.1.0.tgz",
       "integrity": "sha1-DQcLTQQ6W+ozovGkDi7bPZpMz3c="
     },
+    "coffee-script": {
+      "version": "1.12.7",
+      "resolved": "https://registry.npmjs.org/coffee-script/-/coffee-script-1.12.7.tgz",
+      "integrity": "sha512-fLeEhqwymYat/MpTPUjSKHVYYl0ec2mOyALEMLmzr5i1isuG+6jfI2j2d5oBO3VIzgUXgBVIcOT9uH1TFxBckw==",
+      "dev": true
+    },
     "coffeescript": {
       "version": "2.5.1",
       "resolved": "https://registry.npmjs.org/coffeescript/-/coffeescript-2.5.1.tgz",
@@ -1475,7 +1528,7 @@
     "d64": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/d64/-/d64-1.0.0.tgz",
-      "integrity": "sha1-QAKofoUMv8n52XBrYPymE6MzbpA="
+      "integrity": "sha512-5eNy3WZziVYnrogqgXhcdEmqcDB2IHurTqLcrgssJsfkMVCUoUaZpK6cJjxxvLV2dUm5SuJMNcYfVGoin9UIRw=="
     },
     "damerau-levenshtein": {
       "version": "1.0.6",
@@ -1578,9 +1631,9 @@
       "integrity": "sha1-+hN8S9aY7fVc1c0CrFWfkaTEups="
     },
     "diff": {
-      "version": "3.5.0",
-      "resolved": "https://registry.npmjs.org/diff/-/diff-3.5.0.tgz",
-      "integrity": "sha1-gAwN0eCov7yVg1wgKtIg/jF+WhI=",
+      "version": "5.0.0",
+      "resolved": "https://registry.npmjs.org/diff/-/diff-5.0.0.tgz",
+      "integrity": "sha512-/VTCrvm5Z0JGty/BWHljh+BAiw3IK+2j87NGMu8Nwc/f48WoDAC395uomO9ZD117ZOBaHmkX1oyLvkVM/aIT3w==",
       "dev": true
     },
     "diff-match-patch": {
@@ -1747,6 +1800,12 @@
         "is-symbol": "^1.0.2"
       }
     },
+    "escalade": {
+      "version": "3.1.1",
+      "resolved": "https://registry.npmjs.org/escalade/-/escalade-3.1.1.tgz",
+      "integrity": "sha512-k0er2gUkLf8O0zKJiAhmkTnJlTvINGv7ygDNPbeIsX/TJjGJZHuh9B2UxbsaEkmlEo9MfhrSzmhIlhRlI2GXnw==",
+      "dev": true
+    },
     "escape-html": {
       "version": "1.0.3",
       "resolved": "https://registry.npmjs.org/escape-html/-/escape-html-1.0.3.tgz",
@@ -2482,6 +2541,15 @@
       "resolved": "https://registry.npmjs.org/file-uri-to-path/-/file-uri-to-path-1.0.0.tgz",
       "integrity": "sha1-VTp7hEb/b2hDWcRF8eN6BdrMM90="
     },
+    "fill-range": {
+      "version": "7.0.1",
+      "resolved": "https://registry.npmjs.org/fill-range/-/fill-range-7.0.1.tgz",
+      "integrity": "sha512-qOo9F+dMUmC2Lcb4BbVvnKJxTPjCm+RRpe4gDuGrzkL7mEVl/djYSu2OdQ2Pa302N4oqkSg9ir6jaLWJ2USVpQ==",
+      "dev": true,
+      "requires": {
+        "to-regex-range": "^5.0.1"
+      }
+    },
     "finalhandler": {
       "version": "1.1.2",
       "resolved": "https://registry.npmjs.org/finalhandler/-/finalhandler-1.1.2.tgz",
@@ -2510,6 +2578,12 @@
       "resolved": "https://registry.npmjs.org/findit2/-/findit2-2.2.3.tgz",
       "integrity": "sha1-WKRmaX34piBc39vzlVNri9d3pfY="
     },
+    "flat": {
+      "version": "5.0.2",
+      "resolved": "https://registry.npmjs.org/flat/-/flat-5.0.2.tgz",
+      "integrity": "sha512-b6suED+5/3rTpUBdG1gupIl8MPFCAMA0QXwmljLhvCUKcUvdE4gWky9zpuGCcXHOsz4J9wPGNWq6OKpmIzz3hQ==",
+      "dev": true
+    },
     "flat-cache": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/flat-cache/-/flat-cache-2.0.1.tgz",
@@ -2600,6 +2674,13 @@
       "resolved": "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz",
       "integrity": "sha1-FQStJSMVjKpA20onh8sBQRmU6k8="
     },
+    "fsevents": {
+      "version": "2.3.2",
+      "resolved": "https://registry.npmjs.org/fsevents/-/fsevents-2.3.2.tgz",
+      "integrity": "sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==",
+      "dev": true,
+      "optional": true
+    },
     "function-bind": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/function-bind/-/function-bind-1.1.1.tgz",
@@ -2890,9 +2971,9 @@
       "integrity": "sha1-4Ob+aijPUROIVeCG0Wkedx3iqLk="
     },
     "he": {
-      "version": "1.1.1",
-      "resolved": "https://registry.npmjs.org/he/-/he-1.1.1.tgz",
-      "integrity": "sha1-k0EP0hsAlzUVH4howvJx80J+I/0=",
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/he/-/he-1.2.0.tgz",
+      "integrity": "sha512-F/1DnUGPopORZi0ni+CvrCgHQ5FyEAHRLSApuYWMmrbSwoN2Mn/7k+Gl38gJnR7yyDZk6WLXwiGod1JOWNDKGw==",
       "dev": true
     },
     "hex2dec": {
@@ -3245,6 +3326,15 @@
       "integrity": "sha1-d8mYQFJ6qOyxqLppe4BkWnqSap0=",
       "dev": true
     },
+    "is-binary-path": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/is-binary-path/-/is-binary-path-2.1.0.tgz",
+      "integrity": "sha512-ZMERYes6pDydyuGidse7OsHxtbI7WVeUEozgR/g7rd0xUimYNlvZRE/K2MgZTjWy725IfelLeVcEM97mmtRGXw==",
+      "dev": true,
+      "requires": {
+        "binary-extensions": "^2.0.0"
+      }
+    },
     "is-callable": {
       "version": "1.1.5",
       "resolved": "https://registry.npmjs.org/is-callable/-/is-callable-1.1.5.tgz",
@@ -3277,11 +3367,23 @@
         "is-extglob": "^2.1.1"
       }
     },
+    "is-number": {
+      "version": "7.0.0",
+      "resolved": "https://registry.npmjs.org/is-number/-/is-number-7.0.0.tgz",
+      "integrity": "sha512-41Cifkg6e8TylSpdtTpeLVMqvSBEVzTttHvERD741+pnZ8ANv0004MRL43QKPDlK9cGvNp6NZWZUBlbGXYxxng==",
+      "dev": true
+    },
     "is-obj": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/is-obj/-/is-obj-2.0.0.tgz",
       "integrity": "sha512-drqDG3cbczxxEJRoOXcOjtdp1J/lyp1mNn0xaznRs8+muBhgQcrnbspox5X5fOw0HnMnbfDzvnEMEtqDEJEo8w=="
     },
+    "is-plain-obj": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/is-plain-obj/-/is-plain-obj-2.1.0.tgz",
+      "integrity": "sha512-YWnfyRwxL/+SsrWYfOpUtz5b3YD+nyfkHvjbcanzk8zgyO4ASD67uVMRt8k5bM4lLMDnXfriRhOpemw+NfT1eA==",
+      "dev": true
+    },
     "is-regex": {
       "version": "1.0.5",
       "resolved": "https://registry.npmjs.org/is-regex/-/is-regex-1.0.5.tgz",
@@ -3467,12 +3569,12 @@
     "lodash.at": {
       "version": "4.6.0",
       "resolved": "https://registry.npmjs.org/lodash.at/-/lodash.at-4.6.0.tgz",
-      "integrity": "sha1-k83OZk8KGZTqM9181A4jr9EbD/g="
+      "integrity": "sha512-GOTh0SEp+Yosnlpjic+8cl2WM9MykorogkGA9xyIFkkObQ3H3kNZqZ+ohuq4K3FrSVo7hMcZBMataJemrxC3BA=="
     },
     "lodash.camelcase": {
       "version": "4.3.0",
       "resolved": "https://registry.npmjs.org/lodash.camelcase/-/lodash.camelcase-4.3.0.tgz",
-      "integrity": "sha1-soqmKIorn8ZRA1x3EfZathkDMaY="
+      "integrity": "sha512-TwuEnCnxbc3rAvhf/LbG7tJUDzhqXyFnv3dtzLOPgCG/hODL7WFnsbwktkD7yUV0RrreP/l1PALq/YSg6VvjlA=="
     },
     "lodash.defaults": {
       "version": "4.2.0",
@@ -3493,7 +3595,7 @@
     "lodash.has": {
       "version": "4.5.2",
       "resolved": "https://registry.npmjs.org/lodash.has/-/lodash.has-4.5.2.tgz",
-      "integrity": "sha1-0Z9NwQlQWMzL4rDN9O4P5Ko3yGI="
+      "integrity": "sha512-rnYUdIo6xRCJnQmbVFEwcxF144erlD+M3YcJUVesflU9paQaE8p+fJDcIQrlMYbxoANFL+AB9hZrzSBBk5PL+g=="
     },
     "lodash.memoize": {
       "version": "4.1.2",
@@ -3518,6 +3620,66 @@
       "resolved": "https://registry.npmjs.org/log-driver/-/log-driver-1.2.7.tgz",
       "integrity": "sha512-U7KCmLdqsGHBLeWqYlFA0V0Sl6P08EE1ZrmA9cxjUE0WVqT9qnyVDPz1kzpFEP0jdJuFnasWIfSd7fsaNXkpbg=="
     },
+    "log-symbols": {
+      "version": "4.0.0",
+      "resolved": "https://registry.npmjs.org/log-symbols/-/log-symbols-4.0.0.tgz",
+      "integrity": "sha512-FN8JBzLx6CzeMrB0tg6pqlGU1wCrXW+ZXGH481kfsBqer0hToTIiHdjH4Mq8xJUbvATujKCvaREGWpGUionraA==",
+      "dev": true,
+      "requires": {
+        "chalk": "^4.0.0"
+      },
+      "dependencies": {
+        "ansi-styles": {
+          "version": "4.3.0",
+          "resolved": "https://registry.npmjs.org/ansi-styles/-/ansi-styles-4.3.0.tgz",
+          "integrity": "sha512-zbB9rCJAT1rbjiVDb2hqKFHNYLxgtk8NURxZ3IZwD3F6NtxbXZQCnnSi1Lkx+IDohdPlFp222wVALIheZJQSEg==",
+          "dev": true,
+          "requires": {
+            "color-convert": "^2.0.1"
+          }
+        },
+        "chalk": {
+          "version": "4.1.0",
+          "resolved": "https://registry.npmjs.org/chalk/-/chalk-4.1.0.tgz",
+          "integrity": "sha512-qwx12AxXe2Q5xQ43Ac//I6v5aXTipYrSESdOgzrN+9XjgEpyjpKuvSGaN4qE93f7TQTlerQQ8S+EQ0EyDoVL1A==",
+          "dev": true,
+          "requires": {
+            "ansi-styles": "^4.1.0",
+            "supports-color": "^7.1.0"
+          }
+        },
+        "color-convert": {
+          "version": "2.0.1",
+          "resolved": "https://registry.npmjs.org/color-convert/-/color-convert-2.0.1.tgz",
+          "integrity": "sha512-RRECPsj7iu/xb5oKYcsFHSppFNnsj/52OVTRKb4zP5onXwVF3zVmmToNcOfGC+CRDpfK/U584fMg38ZHCaElKQ==",
+          "dev": true,
+          "requires": {
+            "color-name": "~1.1.4"
+          }
+        },
+        "color-name": {
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+      "version": "3.5.0",
+      "resolved": "https://registry.npmjs.org/readdirp/-/readdirp-3.5.0.tgz",
+      "integrity": "sha512-cMhu7c/8rdhkHXWsY+osBhfSy0JikwpHK/5+imo+LpeasTF8ouErHrlYkwT0++njiyuDvc7OFY5T3ukvZ8qmFQ==",
+      "dev": true,
+      "requires": {
+        "picomatch": "^2.2.1"
+      }
+    },
     "redis-commands": {
       "version": "1.5.0",
       "resolved": "https://registry.npmjs.org/redis-commands/-/redis-commands-1.5.0.tgz",
-      "integrity": "sha512-6KxamqpZ468MeQC3bkWmCB1fp56XL64D4Kf0zJSwDZbVLLm7KFkoIcHrgRvQ+sk8dnhySs7+yBg94yIkAK7aJg=="
+      "integrity": "sha1-gNLiBpj+aI8icSf/nlFkp90X54U="
     },
     "redis-errors": {
       "version": "1.2.0",
@@ -5483,7 +5888,7 @@
     "safe-json-stringify": {
       "version": "1.2.0",
       "resolved": "https://registry.npmjs.org/safe-json-stringify/-/safe-json-stringify-1.2.0.tgz",
-      "integrity": "sha512-gH8eh2nZudPQO6TytOvbxnuhYBOvDBBLW52tz5q6X58lJcd/tkmqFR+5Z9adS8aJtURSXWThWy/xJtJwixErvg==",
+      "integrity": "sha1-NW5EvJjx+TzkXfFLzXwBzahuCv0=",
       "optional": true
     },
     "safer-buffer": {
@@ -5492,21 +5897,13 @@
       "integrity": "sha512-YZo3K82SD7Riyi0E1EQPojLz7kpepnSQI9IyPbHHg1XXXevb5dJI7tpyN2ADxGcQbHG7vcyRHk0cbwqcQriUtg=="
     },
     "sandboxed-module": {
-      "version": "0.2.2",
-      "resolved": "https://registry.npmjs.org/sandboxed-module/-/sandboxed-module-0.2.2.tgz",
-      "integrity": "sha1-bL3sghOAx31FdcjIeDi5ET5kulA=",
+      "version": "2.0.4",
+      "resolved": "https://registry.npmjs.org/sandboxed-module/-/sandboxed-module-2.0.4.tgz",
+      "integrity": "sha512-AwEPOdO8mg/wJjr876yCHP2DHqVN0MaggEXhp6IIf3bcI5cYoQl9QrrCHSrvToHjvdEiS5x4TVZRgjD2bEmNTA==",
       "dev": true,
       "requires": {
         "require-like": "0.1.2",
-        "stack-trace": "0.0.6"
-      },
-      "dependencies": {
-        "stack-trace": {
-          "version": "0.0.6",
-          "resolved": "https://registry.npmjs.org/stack-trace/-/stack-trace-0.0.6.tgz",
-          "integrity": "sha1-HnGb1qJin/CcGJ4Xqe+QKpT8XbA=",
-          "dev": true
-        }
+        "stack-trace": "0.0.9"
       }
     },
     "saslprep": {
@@ -5555,6 +5952,15 @@
         }
       }
     },
+    "serialize-javascript": {
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/serialize-javascript/-/serialize-javascript-5.0.1.tgz",
+      "integrity": "sha512-SaaNal9imEO737H2c05Og0/8LUXG7EnsZyMa8MzkmuHoELfT6txuj0cMqRj6zfPKnmQ1yasR4PCJc8x+M4JSPA==",
+      "dev": true,
+      "requires": {
+        "randombytes": "^2.1.0"
+      }
+    },
     "serve-static": {
       "version": "1.14.1",
       "resolved": "https://registry.npmjs.org/serve-static/-/serve-static-1.14.1.tgz",
@@ -5777,7 +6183,7 @@
     "standard-as-callback": {
       "version": "2.0.1",
       "resolved": "https://registry.npmjs.org/standard-as-callback/-/standard-as-callback-2.0.1.tgz",
-      "integrity": "sha512-NQOxSeB8gOI5WjSaxjBgog2QFw55FV8TkS6Y07BiB3VJ8xNTvUYm0wl0s8ObgQ5NhdpnNfigMIKjgPESzgr4tg=="
+      "integrity": "sha1-7YuyVkjhWDF1m2Ajvbh+a2CzgSY="
     },
     "statuses": {
       "version": "1.5.0",
@@ -5896,7 +6302,7 @@
     "stubs": {
       "version": "3.0.0",
       "resolved": "https://registry.npmjs.org/stubs/-/stubs-3.0.0.tgz",
-      "integrity": "sha1-6NK6H6nJBXAwPAMLaQD31fiavls="
+      "integrity": "sha512-PdHt7hHUJKxvTCgbKX9C1V/ftOcjJQgz8BZwNfV5c4B6dcGqlpelTbJ999jBGZ2jYiPAwcX5dP6oBwVlBlUbxw=="
     },
     "supports-color": {
       "version": "5.4.0",
@@ -6028,12 +6434,21 @@
     "to-no-case": {
       "version": "1.0.2",
       "resolved": "https://registry.npmjs.org/to-no-case/-/to-no-case-1.0.2.tgz",
-      "integrity": "sha1-xyKQcWTvaxeBMsjmmTAhLRtKoWo="
+      "integrity": "sha512-Z3g735FxuZY8rodxV4gH7LxClE4H0hTIyHNIHdk+vpQxjLm0cwnKXq/OFVZ76SOQmto7txVcwSCwkU5kqp+FKg=="
+    },
+    "to-regex-range": {
+      "version": "5.0.1",
+      "resolved": "https://registry.npmjs.org/to-regex-range/-/to-regex-range-5.0.1.tgz",
+      "integrity": "sha512-65P7iz6X5yEr1cwcgvQxbbIw7Uk3gOy5dIdtZ4rDveLqhrdJP+Li/Hx6tyK0NEb+2GCyneCMJiGqrADCSNk8sQ==",
+      "dev": true,
+      "requires": {
+        "is-number": "^7.0.0"
+      }
     },
     "to-snake-case": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/to-snake-case/-/to-snake-case-1.0.0.tgz",
-      "integrity": "sha1-znRpE4l5RgGah+Yu366upMYIq4w=",
+      "integrity": "sha512-joRpzBAk1Bhi2eGEYBjukEWHOe/IvclOkiJl3DtA91jV6NwQ3MwXA4FHYeqk8BNp/D8bmi9tcNbRu/SozP0jbQ==",
       "requires": {
         "to-space-case": "^1.0.0"
       }
@@ -6041,7 +6456,7 @@
     "to-space-case": {
       "version": "1.0.0",
       "resolved": "https://registry.npmjs.org/to-space-case/-/to-space-case-1.0.0.tgz",
-      "integrity": "sha1-sFLar7Gysp3HcM6gFj5ewOvJ/Bc=",
+      "integrity": "sha512-rLdvwXZ39VOn1IxGL3V6ZstoTbwLRckQmn/U8ZDLuWwIXNpuZDhQ3AiRUlhTbOXFVE9C+dR51wM0CBDhk31VcA==",
       "requires": {
         "to-no-case": "^1.0.0"
       }
@@ -6322,6 +6737,12 @@
       "integrity": "sha512-Hz/mrNwitNRh/HUAtM/VT/5VH+ygD6DV7mYKZAtHOrbs8U7lvPS6xf7EJKMF0uW1KJCl0H701g3ZGus+muE5vQ==",
       "dev": true
     },
+    "workerpool": {
+      "version": "6.1.0",
+      "resolved": "https://registry.npmjs.org/workerpool/-/workerpool-6.1.0.tgz",
+      "integrity": "sha512-toV7q9rWNYha963Pl/qyeZ6wG+3nnsyvolaNUS8+R5Wtw6qJPTxIlOP1ZSvcGhEJw+l3HMMmtiNo9Gl61G4GVg==",
+      "dev": true
+    },
     "wrap-ansi": {
       "version": "5.1.0",
       "resolved": "https://registry.npmjs.org/wrap-ansi/-/wrap-ansi-5.1.0.tgz",
@@ -6412,6 +6833,32 @@
         "decamelize": "^1.2.0"
       }
     },
+    "yargs-unparser": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/yargs-unparser/-/yargs-unparser-2.0.0.tgz",
+      "integrity": "sha512-7pRTIA9Qc1caZ0bZ6RYRGbHJthJWuakf+WmHK0rVeLkNrrGhfoabBNdue6kdINI6r4if7ocq9aD/n7xwKOdzOA==",
+      "dev": true,
+      "requires": {
+        "camelcase": "^6.0.0",
+        "decamelize": "^4.0.0",
+        "flat": "^5.0.2",
+        "is-plain-obj": "^2.1.0"
+      },
+      "dependencies": {
+        "camelcase": {
+          "version": "6.2.0",
+          "resolved": "https://registry.npmjs.org/camelcase/-/camelcase-6.2.0.tgz",
+          "integrity": "sha512-c7wVvbw3f37nuobQNtgsgG9POC9qMbNuMQmTCqZv23b6MIz0fcYpBiOlv9gEN/hdLdnZTDQhg6e9Dq5M1vKvfg==",
+          "dev": true
+        },
+        "decamelize": {
+          "version": "4.0.0",
+          "resolved": "https://registry.npmjs.org/decamelize/-/decamelize-4.0.0.tgz",
+          "integrity": "sha512-9iE1PgSik9HeIIw2JO94IidnE3eBoQrFJ3w7sFuzSX4DpmZ3v5sZpUiV5Swcf6mQEF+Y0ru8Neo+p+nyh2J+hQ==",
+          "dev": true
+        }
+      }
+    },
     "yn": {
       "version": "3.1.1",
       "resolved": "https://registry.npmjs.org/yn/-/yn-3.1.1.tgz",
diff --git a/services/document-updater/package.json b/services/document-updater/package.json
index 8ea71edddb..a3fb2690cb 100644
--- a/services/document-updater/package.json
+++ b/services/document-updater/package.json
@@ -36,8 +36,8 @@
   "devDependencies": {
     "babel-eslint": "^10.1.0",
     "chai": "^3.5.0",
-    "chai-spies": "^0.7.1",
     "cluster-key-slot": "^1.0.5",
+    "coffee-script": "^1.12.7",
     "eslint": "^6.8.0",
     "eslint-config-prettier": "^6.10.0",
     "eslint-config-standard": "^14.1.0",
@@ -53,10 +53,10 @@
     "eslint-plugin-promise": "^4.2.1",
     "eslint-plugin-react": "^7.19.0",
     "eslint-plugin-standard": "^4.0.1",
-    "mocha": "^5.0.1",
+    "mocha": "^8.3.2",
     "prettier": "^2.0.0",
     "prettier-eslint-cli": "^5.0.0",
-    "sandboxed-module": "~0.2.0",
+    "sandboxed-module": "^2.0.4",
     "sinon": "^9.0.2",
     "timekeeper": "^2.0.0"
   }
diff --git a/services/document-updater/test/acceptance/js/ApplyingUpdatesToADocTests.js b/services/document-updater/test/acceptance/js/ApplyingUpdatesToADocTests.js
index f460a2d3ff..adf045645e 100644
--- a/services/document-updater/test/acceptance/js/ApplyingUpdatesToADocTests.js
+++ b/services/document-updater/test/acceptance/js/ApplyingUpdatesToADocTests.js
@@ -12,9 +12,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 const async = require('async')
 const Settings = require('settings-sharelatex')
 const rclient_history = require('@overleaf/redis-wrapper').createClient(
diff --git a/services/document-updater/test/acceptance/js/ApplyingUpdatesToProjectStructureTests.js b/services/document-updater/test/acceptance/js/ApplyingUpdatesToProjectStructureTests.js
index 42c3c8af6a..3bc2c793e1 100644
--- a/services/document-updater/test/acceptance/js/ApplyingUpdatesToProjectStructureTests.js
+++ b/services/document-updater/test/acceptance/js/ApplyingUpdatesToProjectStructureTests.js
@@ -1,6 +1,4 @@
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
 const Settings = require('settings-sharelatex')
 const rclientProjectHistory = require('@overleaf/redis-wrapper').createClient(
   Settings.redis.project_history
diff --git a/services/document-updater/test/acceptance/js/DeletingADocumentTests.js b/services/document-updater/test/acceptance/js/DeletingADocumentTests.js
index fbb8055aae..4051d4f5a4 100644
--- a/services/document-updater/test/acceptance/js/DeletingADocumentTests.js
+++ b/services/document-updater/test/acceptance/js/DeletingADocumentTests.js
@@ -11,9 +11,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
-
 const MockTrackChangesApi = require('./helpers/MockTrackChangesApi')
 const MockProjectHistoryApi = require('./helpers/MockProjectHistoryApi')
 const MockWebApi = require('./helpers/MockWebApi')
diff --git a/services/document-updater/test/acceptance/js/DeletingAProjectTests.js b/services/document-updater/test/acceptance/js/DeletingAProjectTests.js
index f050ea22e1..b07ffae0f5 100644
--- a/services/document-updater/test/acceptance/js/DeletingAProjectTests.js
+++ b/services/document-updater/test/acceptance/js/DeletingAProjectTests.js
@@ -12,8 +12,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
 const async = require('async')
 
 const MockTrackChangesApi = require('./helpers/MockTrackChangesApi')
diff --git a/services/document-updater/test/acceptance/js/FlushingAProjectTests.js b/services/document-updater/test/acceptance/js/FlushingAProjectTests.js
index c860fce849..4f4abc2730 100644
--- a/services/document-updater/test/acceptance/js/FlushingAProjectTests.js
+++ b/services/document-updater/test/acceptance/js/FlushingAProjectTests.js
@@ -12,8 +12,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
 const async = require('async')
 
 const MockWebApi = require('./helpers/MockWebApi')
diff --git a/services/document-updater/test/acceptance/js/FlushingDocsTests.js b/services/document-updater/test/acceptance/js/FlushingDocsTests.js
index 109f89d434..5eac9fa2f3 100644
--- a/services/document-updater/test/acceptance/js/FlushingDocsTests.js
+++ b/services/document-updater/test/acceptance/js/FlushingDocsTests.js
@@ -14,9 +14,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 const async = require('async')
 
 const MockWebApi = require('./helpers/MockWebApi')
diff --git a/services/document-updater/test/acceptance/js/GettingADocumentTests.js b/services/document-updater/test/acceptance/js/GettingADocumentTests.js
index a0b9de5773..50dc35059c 100644
--- a/services/document-updater/test/acceptance/js/GettingADocumentTests.js
+++ b/services/document-updater/test/acceptance/js/GettingADocumentTests.js
@@ -12,9 +12,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 
 const MockWebApi = require('./helpers/MockWebApi')
 const DocUpdaterClient = require('./helpers/DocUpdaterClient')
diff --git a/services/document-updater/test/acceptance/js/GettingProjectDocsTests.js b/services/document-updater/test/acceptance/js/GettingProjectDocsTests.js
index 72a6824562..b32ccb0837 100644
--- a/services/document-updater/test/acceptance/js/GettingProjectDocsTests.js
+++ b/services/document-updater/test/acceptance/js/GettingProjectDocsTests.js
@@ -12,9 +12,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 
 const MockWebApi = require('./helpers/MockWebApi')
 const DocUpdaterClient = require('./helpers/DocUpdaterClient')
diff --git a/services/document-updater/test/acceptance/js/RangesTests.js b/services/document-updater/test/acceptance/js/RangesTests.js
index b765e58b7c..7034436440 100644
--- a/services/document-updater/test/acceptance/js/RangesTests.js
+++ b/services/document-updater/test/acceptance/js/RangesTests.js
@@ -12,9 +12,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 const async = require('async')
 
 const { db, ObjectId } = require('../../../app/js/mongodb')
diff --git a/services/document-updater/test/acceptance/js/SettingADocumentTests.js b/services/document-updater/test/acceptance/js/SettingADocumentTests.js
index d47931868c..7d2307c526 100644
--- a/services/document-updater/test/acceptance/js/SettingADocumentTests.js
+++ b/services/document-updater/test/acceptance/js/SettingADocumentTests.js
@@ -1,6 +1,4 @@
 const sinon = require('sinon')
-const chai = require('chai')
-chai.should()
 const { expect } = require('chai')
 const Settings = require('settings-sharelatex')
 const docUpdaterRedis = require('@overleaf/redis-wrapper').createClient(
diff --git a/services/document-updater/test/setup.js b/services/document-updater/test/setup.js
new file mode 100644
index 0000000000..0fb9848427
--- /dev/null
+++ b/services/document-updater/test/setup.js
@@ -0,0 +1,37 @@
+const chai = require('chai')
+const SandboxedModule = require('sandboxed-module')
+const sinon = require('sinon')
+
+// Chai configuration
+chai.should()
+
+// Global stubs
+const sandbox = sinon.createSandbox()
+const stubs = {
+  logger: {
+    debug: sandbox.stub(),
+    log: sandbox.stub(),
+    warn: sandbox.stub(),
+    err: sandbox.stub(),
+    error: sandbox.stub()
+  }
+}
+
+// SandboxedModule configuration
+SandboxedModule.configure({
+  requires: {
+    'logger-sharelatex': stubs.logger
+  },
+  globals: { Buffer, JSON, Math, console, process }
+})
+
+// Mocha hooks
+exports.mochaHooks = {
+  beforeEach() {
+    this.logger = stubs.logger
+  },
+
+  afterEach() {
+    sandbox.reset()
+  }
+}
diff --git a/services/document-updater/test/unit/js/DiffCodec/DiffCodecTests.js b/services/document-updater/test/unit/js/DiffCodec/DiffCodecTests.js
index f208c17bd6..d498d6b45c 100644
--- a/services/document-updater/test/unit/js/DiffCodec/DiffCodecTests.js
+++ b/services/document-updater/test/unit/js/DiffCodec/DiffCodecTests.js
@@ -11,9 +11,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 const modulePath = '../../../../app/js/DiffCodec.js'
 const SandboxedModule = require('sandboxed-module')
 
diff --git a/services/document-updater/test/unit/js/DispatchManager/DispatchManagerTests.js b/services/document-updater/test/unit/js/DispatchManager/DispatchManagerTests.js
index 5610c4abc1..81ef37f4be 100644
--- a/services/document-updater/test/unit/js/DispatchManager/DispatchManagerTests.js
+++ b/services/document-updater/test/unit/js/DispatchManager/DispatchManagerTests.js
@@ -12,8 +12,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/DispatchManager.js'
 const SandboxedModule = require('sandboxed-module')
 const Errors = require('../../../../app/js/Errors.js')
@@ -25,11 +23,6 @@ describe('DispatchManager', function () {
     this.DispatchManager = SandboxedModule.require(modulePath, {
       requires: {
         './UpdateManager': (this.UpdateManager = {}),
-        'logger-sharelatex': (this.logger = {
-          log: sinon.stub(),
-          error: sinon.stub(),
-          warn: sinon.stub()
-        }),
         'settings-sharelatex': (this.settings = {
           redis: {
             documentupdater: {}
diff --git a/services/document-updater/test/unit/js/DocumentManager/DocumentManagerTests.js b/services/document-updater/test/unit/js/DocumentManager/DocumentManagerTests.js
index 295a643cee..8ca42df757 100644
--- a/services/document-updater/test/unit/js/DocumentManager/DocumentManagerTests.js
+++ b/services/document-updater/test/unit/js/DocumentManager/DocumentManagerTests.js
@@ -13,8 +13,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/DocumentManager.js'
 const SandboxedModule = require('sandboxed-module')
 const Errors = require('../../../../app/js/Errors')
@@ -33,11 +31,6 @@ describe('DocumentManager', function () {
           flushDocChangesAsync: sinon.stub(),
           flushProjectChangesAsync: sinon.stub()
         }),
-        'logger-sharelatex': (this.logger = {
-          log: sinon.stub(),
-          warn: sinon.stub()
-        }),
-        './DocOpsManager': (this.DocOpsManager = {}),
         './Metrics': (this.Metrics = {
           Timer: (Timer = (function () {
             Timer = class Timer {
@@ -220,7 +213,6 @@ describe('DocumentManager', function () {
           .stub()
           .callsArgWith(2, null, null, null, null)
         this.PersistenceManager.setDoc = sinon.stub().yields()
-        this.DocOpsManager.flushDocOpsToMongo = sinon.stub().callsArgWith(2)
         return this.DocumentManager.flushDocIfLoaded(
           this.project_id,
           this.doc_id,
@@ -236,7 +228,6 @@ describe('DocumentManager', function () {
 
       it('should not write anything to the persistence layer', function () {
         this.PersistenceManager.setDoc.called.should.equal(false)
-        return this.DocOpsManager.flushDocOpsToMongo.called.should.equal(false)
       })
 
       it('should call the callback without error', function () {
diff --git a/services/document-updater/test/unit/js/HistoryManager/HistoryManagerTests.js b/services/document-updater/test/unit/js/HistoryManager/HistoryManagerTests.js
index 263f1cd094..df3261b0f4 100644
--- a/services/document-updater/test/unit/js/HistoryManager/HistoryManagerTests.js
+++ b/services/document-updater/test/unit/js/HistoryManager/HistoryManagerTests.js
@@ -11,7 +11,6 @@
  */
 const SandboxedModule = require('sandboxed-module')
 const sinon = require('sinon')
-require('chai').should()
 const modulePath = require('path').join(
   __dirname,
   '../../../../app/js/HistoryManager'
@@ -33,11 +32,6 @@ describe('HistoryManager', function () {
             }
           }
         }),
-        'logger-sharelatex': (this.logger = {
-          log: sinon.stub(),
-          error: sinon.stub(),
-          debug: sinon.stub()
-        }),
         './DocumentManager': (this.DocumentManager = {}),
         './HistoryRedisManager': (this.HistoryRedisManager = {}),
         './RedisManager': (this.RedisManager = {}),
diff --git a/services/document-updater/test/unit/js/HistoryRedisManager/HistoryRedisManagerTests.js b/services/document-updater/test/unit/js/HistoryRedisManager/HistoryRedisManagerTests.js
index 1b266685d1..f9b719991a 100644
--- a/services/document-updater/test/unit/js/HistoryRedisManager/HistoryRedisManagerTests.js
+++ b/services/document-updater/test/unit/js/HistoryRedisManager/HistoryRedisManagerTests.js
@@ -12,8 +12,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/HistoryRedisManager.js'
 const SandboxedModule = require('sandboxed-module')
 const Errors = require('../../../../app/js/Errors')
@@ -41,8 +39,7 @@ describe('HistoryRedisManager', function () {
               }
             })
           }
-        },
-        'logger-sharelatex': { log() {} }
+        }
       }
     })
     this.doc_id = 'doc-id-123'
diff --git a/services/document-updater/test/unit/js/HttpController/HttpControllerTests.js b/services/document-updater/test/unit/js/HttpController/HttpControllerTests.js
index 07e9d93c9a..64477eb944 100644
--- a/services/document-updater/test/unit/js/HttpController/HttpControllerTests.js
+++ b/services/document-updater/test/unit/js/HttpController/HttpControllerTests.js
@@ -12,7 +12,6 @@ describe('HttpController', function () {
           flushProjectChangesAsync: sinon.stub()
         }),
         './ProjectManager': (this.ProjectManager = {}),
-        'logger-sharelatex': (this.logger = { log: sinon.stub() }),
         './ProjectFlusher': { flushAllProjects() {} },
         './DeleteQueueManager': (this.DeleteQueueManager = {}),
         './Metrics': (this.Metrics = {}),
diff --git a/services/document-updater/test/unit/js/LockManager/CheckingTheLock.js b/services/document-updater/test/unit/js/LockManager/CheckingTheLock.js
index 6b3c3b539e..4f700cc144 100644
--- a/services/document-updater/test/unit/js/LockManager/CheckingTheLock.js
+++ b/services/document-updater/test/unit/js/LockManager/CheckingTheLock.js
@@ -25,7 +25,6 @@ describe('LockManager - checking the lock', function () {
   const existsStub = sinon.stub()
 
   const mocks = {
-    'logger-sharelatex': { log() {} },
     '@overleaf/redis-wrapper': {
       createClient() {
         return {
diff --git a/services/document-updater/test/unit/js/LockManager/ReleasingTheLock.js b/services/document-updater/test/unit/js/LockManager/ReleasingTheLock.js
index a04db7614f..3d6cf7a5ba 100644
--- a/services/document-updater/test/unit/js/LockManager/ReleasingTheLock.js
+++ b/services/document-updater/test/unit/js/LockManager/ReleasingTheLock.js
@@ -27,10 +27,6 @@ describe('LockManager - releasing the lock', function () {
       eval: sinon.stub()
     }
     const mocks = {
-      'logger-sharelatex': {
-        log() {},
-        error() {}
-      },
       '@overleaf/redis-wrapper': {
         createClient: () => this.client
       },
diff --git a/services/document-updater/test/unit/js/LockManager/getLockTests.js b/services/document-updater/test/unit/js/LockManager/getLockTests.js
index d56a244510..0b938c3753 100644
--- a/services/document-updater/test/unit/js/LockManager/getLockTests.js
+++ b/services/document-updater/test/unit/js/LockManager/getLockTests.js
@@ -15,8 +15,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/LockManager.js'
 const SandboxedModule = require('sandboxed-module')
 
@@ -25,7 +23,6 @@ describe('LockManager - getting the lock', function () {
     let Profiler
     this.LockManager = SandboxedModule.require(modulePath, {
       requires: {
-        'logger-sharelatex': { log() {} },
         '@overleaf/redis-wrapper': {
           createClient: () => {
             return { auth() {} }
diff --git a/services/document-updater/test/unit/js/LockManager/tryLockTests.js b/services/document-updater/test/unit/js/LockManager/tryLockTests.js
index 02c279dd11..fb49e94aa1 100644
--- a/services/document-updater/test/unit/js/LockManager/tryLockTests.js
+++ b/services/document-updater/test/unit/js/LockManager/tryLockTests.js
@@ -12,8 +12,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/LockManager.js'
 const SandboxedModule = require('sandboxed-module')
 
@@ -22,7 +20,6 @@ describe('LockManager - trying the lock', function () {
     let Profiler
     this.LockManager = SandboxedModule.require(modulePath, {
       requires: {
-        'logger-sharelatex': { log() {} },
         '@overleaf/redis-wrapper': {
           createClient: () => {
             return {
diff --git a/services/document-updater/test/unit/js/PersistenceManager/PersistenceManagerTests.js b/services/document-updater/test/unit/js/PersistenceManager/PersistenceManagerTests.js
index 1013752dee..4015ef2662 100644
--- a/services/document-updater/test/unit/js/PersistenceManager/PersistenceManagerTests.js
+++ b/services/document-updater/test/unit/js/PersistenceManager/PersistenceManagerTests.js
@@ -11,8 +11,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/PersistenceManager.js'
 const SandboxedModule = require('sandboxed-module')
 const Errors = require('../../../../app/js/Errors')
@@ -38,11 +36,6 @@ describe('PersistenceManager', function () {
           })()),
           inc: sinon.stub()
         }),
-        'logger-sharelatex': (this.logger = {
-          log: sinon.stub(),
-          err: sinon.stub(),
-          error: sinon.stub()
-        }),
         './Errors': Errors
       }
     })
diff --git a/services/document-updater/test/unit/js/ProjectHistoryRedisManager/ProjectHistoryRedisManagerTests.js b/services/document-updater/test/unit/js/ProjectHistoryRedisManager/ProjectHistoryRedisManagerTests.js
index 8b62bd83f3..1ff3d53ded 100644
--- a/services/document-updater/test/unit/js/ProjectHistoryRedisManager/ProjectHistoryRedisManagerTests.js
+++ b/services/document-updater/test/unit/js/ProjectHistoryRedisManager/ProjectHistoryRedisManagerTests.js
@@ -12,8 +12,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/ProjectHistoryRedisManager.js'
 const SandboxedModule = require('sandboxed-module')
 const tk = require('timekeeper')
@@ -47,13 +45,7 @@ describe('ProjectHistoryRedisManager', function () {
           '@overleaf/redis-wrapper': {
             createClient: () => this.rclient
           },
-          'logger-sharelatex': {
-            log() {}
-          },
           './Metrics': (this.metrics = { summary: sinon.stub() })
-        },
-        globals: {
-          JSON: (this.JSON = JSON)
         }
       }
     ))
@@ -136,7 +128,7 @@ describe('ProjectHistoryRedisManager', function () {
       return this.ProjectHistoryRedisManager.queueOps
         .calledWithExactly(
           this.project_id,
-          this.JSON.stringify(update),
+          JSON.stringify(update),
           this.callback
         )
         .should.equal(true)
@@ -184,7 +176,7 @@ describe('ProjectHistoryRedisManager', function () {
       return this.ProjectHistoryRedisManager.queueOps
         .calledWithExactly(
           this.project_id,
-          this.JSON.stringify(update),
+          JSON.stringify(update),
           this.callback
         )
         .should.equal(true)
diff --git a/services/document-updater/test/unit/js/ProjectManager/flushAndDeleteProjectTests.js b/services/document-updater/test/unit/js/ProjectManager/flushAndDeleteProjectTests.js
index 9589d42054..d8342c0cff 100644
--- a/services/document-updater/test/unit/js/ProjectManager/flushAndDeleteProjectTests.js
+++ b/services/document-updater/test/unit/js/ProjectManager/flushAndDeleteProjectTests.js
@@ -13,8 +13,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/ProjectManager.js'
 const SandboxedModule = require('sandboxed-module')
 
@@ -26,10 +24,6 @@ describe('ProjectManager - flushAndDeleteProject', function () {
         './RedisManager': (this.RedisManager = {}),
         './ProjectHistoryRedisManager': (this.ProjectHistoryRedisManager = {}),
         './DocumentManager': (this.DocumentManager = {}),
-        'logger-sharelatex': (this.logger = {
-          log: sinon.stub(),
-          error: sinon.stub()
-        }),
         './HistoryManager': (this.HistoryManager = {
           flushProjectChanges: sinon.stub().callsArg(2)
         }),
diff --git a/services/document-updater/test/unit/js/ProjectManager/flushProjectTests.js b/services/document-updater/test/unit/js/ProjectManager/flushProjectTests.js
index c0bb668f49..70ae03e861 100644
--- a/services/document-updater/test/unit/js/ProjectManager/flushProjectTests.js
+++ b/services/document-updater/test/unit/js/ProjectManager/flushProjectTests.js
@@ -15,8 +15,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/ProjectManager.js'
 const SandboxedModule = require('sandboxed-module')
 
@@ -28,10 +26,6 @@ describe('ProjectManager - flushProject', function () {
         './RedisManager': (this.RedisManager = {}),
         './ProjectHistoryRedisManager': (this.ProjectHistoryRedisManager = {}),
         './DocumentManager': (this.DocumentManager = {}),
-        'logger-sharelatex': (this.logger = {
-          log: sinon.stub(),
-          error: sinon.stub()
-        }),
         './HistoryManager': (this.HistoryManager = {}),
         './Metrics': (this.Metrics = {
           Timer: (Timer = (function () {
diff --git a/services/document-updater/test/unit/js/ProjectManager/getProjectDocsTests.js b/services/document-updater/test/unit/js/ProjectManager/getProjectDocsTests.js
index db9f31e4ad..467a190168 100644
--- a/services/document-updater/test/unit/js/ProjectManager/getProjectDocsTests.js
+++ b/services/document-updater/test/unit/js/ProjectManager/getProjectDocsTests.js
@@ -11,8 +11,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/ProjectManager.js'
 const SandboxedModule = require('sandboxed-module')
 const Errors = require('../../../../app/js/Errors.js')
@@ -25,10 +23,6 @@ describe('ProjectManager - getProjectDocsAndFlushIfOld', function () {
         './RedisManager': (this.RedisManager = {}),
         './ProjectHistoryRedisManager': (this.ProjectHistoryRedisManager = {}),
         './DocumentManager': (this.DocumentManager = {}),
-        'logger-sharelatex': (this.logger = {
-          log: sinon.stub(),
-          error: sinon.stub()
-        }),
         './HistoryManager': (this.HistoryManager = {}),
         './Metrics': (this.Metrics = {
           Timer: (Timer = (function () {
diff --git a/services/document-updater/test/unit/js/ProjectManager/updateProjectTests.js b/services/document-updater/test/unit/js/ProjectManager/updateProjectTests.js
index aa3db813a0..896517679c 100644
--- a/services/document-updater/test/unit/js/ProjectManager/updateProjectTests.js
+++ b/services/document-updater/test/unit/js/ProjectManager/updateProjectTests.js
@@ -22,17 +22,11 @@ describe('ProjectManager', function () {
     }
     this.Metrics.Timer.prototype.done = sinon.stub()
 
-    this.logger = {
-      log: sinon.stub(),
-      error: sinon.stub()
-    }
-
     this.ProjectManager = SandboxedModule.require(modulePath, {
       requires: {
         './RedisManager': this.RedisManager,
         './ProjectHistoryRedisManager': this.ProjectHistoryRedisManager,
         './DocumentManager': this.DocumentManager,
-        'logger-sharelatex': this.logger,
         './HistoryManager': this.HistoryManager,
         './Metrics': this.Metrics
       }
diff --git a/services/document-updater/test/unit/js/RangesManager/RangesManagerTests.js b/services/document-updater/test/unit/js/RangesManager/RangesManagerTests.js
index a336125a1c..c857153888 100644
--- a/services/document-updater/test/unit/js/RangesManager/RangesManagerTests.js
+++ b/services/document-updater/test/unit/js/RangesManager/RangesManagerTests.js
@@ -13,23 +13,13 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 const modulePath = '../../../../app/js/RangesManager.js'
 const SandboxedModule = require('sandboxed-module')
 
 describe('RangesManager', function () {
   beforeEach(function () {
-    this.RangesManager = SandboxedModule.require(modulePath, {
-      requires: {
-        'logger-sharelatex': (this.logger = {
-          error: sinon.stub(),
-          log: sinon.stub(),
-          warn: sinon.stub()
-        })
-      }
-    })
+    this.RangesManager = SandboxedModule.require(modulePath)
 
     this.doc_id = 'doc-id-123'
     this.project_id = 'project-id-123'
@@ -368,11 +358,6 @@ describe('RangesManager', function () {
     beforeEach(function () {
       this.RangesManager = SandboxedModule.require(modulePath, {
         requires: {
-          'logger-sharelatex': (this.logger = {
-            error: sinon.stub(),
-            log: sinon.stub(),
-            warn: sinon.stub()
-          }),
           './RangesTracker': (this.RangesTracker = SandboxedModule.require(
             '../../../../app/js/RangesTracker.js'
           ))
diff --git a/services/document-updater/test/unit/js/RateLimitManager/RateLimitManager.js b/services/document-updater/test/unit/js/RateLimitManager/RateLimitManager.js
index e84d557501..8fef08051f 100644
--- a/services/document-updater/test/unit/js/RateLimitManager/RateLimitManager.js
+++ b/services/document-updater/test/unit/js/RateLimitManager/RateLimitManager.js
@@ -11,9 +11,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 const modulePath = '../../../../app/js/RateLimitManager.js'
 const SandboxedModule = require('sandboxed-module')
 
@@ -22,7 +20,6 @@ describe('RateLimitManager', function () {
     let Timer
     this.RateLimitManager = SandboxedModule.require(modulePath, {
       requires: {
-        'logger-sharelatex': (this.logger = { log: sinon.stub() }),
         'settings-sharelatex': (this.settings = {}),
         './Metrics': (this.Metrics = {
           Timer: (Timer = (function () {
diff --git a/services/document-updater/test/unit/js/RealTimeRedisManager/RealTimeRedisManagerTests.js b/services/document-updater/test/unit/js/RealTimeRedisManager/RealTimeRedisManagerTests.js
index c5e4647df4..83cd5f99ce 100644
--- a/services/document-updater/test/unit/js/RealTimeRedisManager/RealTimeRedisManagerTests.js
+++ b/services/document-updater/test/unit/js/RealTimeRedisManager/RealTimeRedisManagerTests.js
@@ -11,8 +11,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/RealTimeRedisManager.js'
 const SandboxedModule = require('sandboxed-module')
 const Errors = require('../../../../app/js/Errors')
@@ -45,7 +43,6 @@ describe('RealTimeRedisManager', function () {
             }
           }
         },
-        'logger-sharelatex': { log() {} },
         crypto: (this.crypto = {
           randomBytes: sinon
             .stub()
diff --git a/services/document-updater/test/unit/js/RedisManager/RedisManagerTests.js b/services/document-updater/test/unit/js/RedisManager/RedisManagerTests.js
index 739aa88ab8..d14d0c23de 100644
--- a/services/document-updater/test/unit/js/RedisManager/RedisManagerTests.js
+++ b/services/document-updater/test/unit/js/RedisManager/RedisManagerTests.js
@@ -12,8 +12,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/RedisManager.js'
 const SandboxedModule = require('sandboxed-module')
 const Errors = require('../../../../app/js/Errors')
@@ -28,11 +26,6 @@ describe('RedisManager', function () {
     tk.freeze(new Date())
     this.RedisManager = SandboxedModule.require(modulePath, {
       requires: {
-        'logger-sharelatex': (this.logger = {
-          error: sinon.stub(),
-          log: sinon.stub(),
-          warn: sinon.stub()
-        }),
         './ProjectHistoryRedisManager': (this.ProjectHistoryRedisManager = {}),
         'settings-sharelatex': (this.settings = {
           documentupdater: { logHashErrors: { write: true, read: true } },
@@ -122,9 +115,6 @@ describe('RedisManager', function () {
           })
         }),
         './Errors': Errors
-      },
-      globals: {
-        JSON: (this.JSON = JSON)
       }
     })
 
@@ -924,8 +914,9 @@ describe('RedisManager', function () {
         this.RedisManager.getDocVersion
           .withArgs(this.doc_id)
           .yields(null, this.version - this.ops.length)
-        this._stringify = JSON.stringify
-        this.JSON.stringify = () => '["bad bytes! \u0000 <- here"]'
+        this.stringifyStub = sinon
+          .stub(JSON, 'stringify')
+          .callsFake(() => '["bad bytes! \u0000 <- here"]')
         return this.RedisManager.updateDocument(
           this.project_id,
           this.doc_id,
@@ -939,7 +930,7 @@ describe('RedisManager', function () {
       })
 
       afterEach(function () {
-        return (this.JSON.stringify = this._stringify)
+        this.stringifyStub.restore()
       })
 
       it('should log an error', function () {
@@ -1127,8 +1118,9 @@ describe('RedisManager', function () {
 
     describe('with null bytes in the serialized doc lines', function () {
       beforeEach(function () {
-        this._stringify = JSON.stringify
-        this.JSON.stringify = () => '["bad bytes! \u0000 <- here"]'
+        this.stringifyStub = sinon
+          .stub(JSON, 'stringify')
+          .callsFake(() => '["bad bytes! \u0000 <- here"]')
         return this.RedisManager.putDocInMemory(
           this.project_id,
           this.doc_id,
@@ -1142,7 +1134,7 @@ describe('RedisManager', function () {
       })
 
       afterEach(function () {
-        return (this.JSON.stringify = this._stringify)
+        this.stringifyStub.restore()
       })
 
       it('should log an error', function () {
diff --git a/services/document-updater/test/unit/js/ShareJS/TextTransformTests.js b/services/document-updater/test/unit/js/ShareJS/TextTransformTests.js
index 8ea99aee5c..a5e3a8599a 100644
--- a/services/document-updater/test/unit/js/ShareJS/TextTransformTests.js
+++ b/services/document-updater/test/unit/js/ShareJS/TextTransformTests.js
@@ -14,7 +14,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const text = require('../../../../app/js/sharejs/types/text')
-require('chai').should()
 const RangesTracker = require('../../../../app/js/RangesTracker')
 
 describe('ShareJS text type', function () {
diff --git a/services/document-updater/test/unit/js/ShareJsDB/ShareJsDBTests.js b/services/document-updater/test/unit/js/ShareJsDB/ShareJsDBTests.js
index ddf98775d8..1b4e4422a6 100644
--- a/services/document-updater/test/unit/js/ShareJsDB/ShareJsDBTests.js
+++ b/services/document-updater/test/unit/js/ShareJsDB/ShareJsDBTests.js
@@ -11,9 +11,7 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
-const { expect } = chai
+const { expect } = require('chai')
 const modulePath = '../../../../app/js/ShareJsDB.js'
 const SandboxedModule = require('sandboxed-module')
 const Errors = require('../../../../app/js/Errors')
diff --git a/services/document-updater/test/unit/js/ShareJsUpdateManager/ShareJsUpdateManagerTests.js b/services/document-updater/test/unit/js/ShareJsUpdateManager/ShareJsUpdateManagerTests.js
index 2ab5ba617e..d6e9700bff 100644
--- a/services/document-updater/test/unit/js/ShareJsUpdateManager/ShareJsUpdateManagerTests.js
+++ b/services/document-updater/test/unit/js/ShareJsUpdateManager/ShareJsUpdateManagerTests.js
@@ -10,8 +10,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/ShareJsUpdateManager.js'
 const SandboxedModule = require('sandboxed-module')
 const crypto = require('crypto')
@@ -35,7 +33,6 @@ describe('ShareJsUpdateManager', function () {
             return (this.rclient = { auth() {} })
           }
         },
-        'logger-sharelatex': (this.logger = { log: sinon.stub() }),
         './RealTimeRedisManager': (this.RealTimeRedisManager = {}),
         './Metrics': (this.metrics = { inc: sinon.stub() })
       },
diff --git a/services/document-updater/test/unit/js/UpdateManager/UpdateManagerTests.js b/services/document-updater/test/unit/js/UpdateManager/UpdateManagerTests.js
index 4e39089490..cac51b9f5f 100644
--- a/services/document-updater/test/unit/js/UpdateManager/UpdateManagerTests.js
+++ b/services/document-updater/test/unit/js/UpdateManager/UpdateManagerTests.js
@@ -12,8 +12,6 @@
  * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
  */
 const sinon = require('sinon')
-const chai = require('chai')
-const should = chai.should()
 const modulePath = '../../../../app/js/UpdateManager.js'
 const SandboxedModule = require('sandboxed-module')
 
@@ -31,7 +29,6 @@ describe('UpdateManager', function () {
         './RealTimeRedisManager': (this.RealTimeRedisManager = {}),
         './ShareJsUpdateManager': (this.ShareJsUpdateManager = {}),
         './HistoryManager': (this.HistoryManager = {}),
-        'logger-sharelatex': (this.logger = { log: sinon.stub() }),
         './Metrics': (this.Metrics = {
           Timer: (Timer = (function () {
             Timer = class Timer {