diff --git a/migrations/3_pack_docHistory_collection.coffee b/migrations/3_pack_docHistory_collection.coffee
new file mode 100644
index 0000000000..dd8d750115
--- /dev/null
+++ b/migrations/3_pack_docHistory_collection.coffee
@@ -0,0 +1,291 @@
+Settings = require "settings-sharelatex"
+fs = require("fs")
+mongojs = require("mongojs")
+ObjectId = mongojs.ObjectId
+db = mongojs(Settings.mongo.url, ['docs','docHistory', 'docHistoryStats'])
+_ = require("lodash")
+async = require("async")
+exec = require("child_process").exec
+BSON = db.bson.BSON
+
+logger = {
+	log: ->
+	err: ->
+}
+
+finished_docs_path = "/tmp/finished-docs-3"
+all_docs_path = "/tmp/all-docs-3"
+unmigrated_docs_path = "/tmp/unmigrated-docs-3"
+
+finished_docs = {}
+if fs.existsSync(finished_docs_path)
+	for id in fs.readFileSync(finished_docs_path,'utf-8').split("\n")
+		finished_docs[id] = true
+
+getAndWriteDocids = (callback)->
+	console.log "finding all doc id's - #{new Date().toString()}"
+	db.docs.find {}, {_id:1}, (err, ids)->
+		console.log "total found docs in mongo #{ids.length} - #{new Date().toString()}"
+		ids = _.pluck ids, '_id'
+		ids = _.filter ids, (id)-> id?
+		fileData = ids.join("\n")
+		fs.writeFileSync all_docs_path + ".tmp", fileData
+		fs.renameSync all_docs_path + ".tmp", all_docs_path
+		callback(err, ids)
+
+loadDocIds = (callback)->
+	console.log "loading doc ids from #{all_docs_path}"
+	data = fs.readFileSync all_docs_path, "utf-8"
+	ids = data.split("\n")
+	console.log "loaded #{ids.length} doc ids from #{all_docs_path}"
+	callback null, ids
+
+getDocIds = (callback)->
+	exists = fs.existsSync all_docs_path
+	if exists
+		loadDocIds callback
+	else
+		getAndWriteDocids callback
+
+markDocAsProcessed = (doc_id, callback)->
+	finished_docs[doc_id] = true
+	fs.appendFile finished_docs_path, "#{doc_id}\n", callback
+
+markDocAsUnmigrated = (doc_id, callback)->
+	console.log "#{doc_id} unmigrated"
+	markDocAsProcessed doc_id, (err)->
+		fs.appendFile unmigrated_docs_path, "#{doc_id}\n", callback
+
+printProgress = ->
+	count = Object.keys(finished_docs).length
+	console.log "completed", count
+
+checkIfDocHasBeenProccessed = (doc_id, callback)->
+	callback(null, finished_docs[doc_id])
+
+processNext = (doc_id, callback)->
+	if !doc_id? or doc_id.length == 0
+		return callback()
+	checkIfDocHasBeenProccessed doc_id, (err, hasBeenProcessed)->
+		if hasBeenProcessed
+			console.log "#{doc_id} already processed, skipping"
+			return callback()
+		console.log "#{doc_id} processing"
+		PackManager._packDocHistory doc_id, {}, (err) ->
+			markDocAsProcessed doc_id, callback
+
+exports.migrate = (client, done = ->)->
+	getDocIds (err, ids)->
+		interval = setInterval printProgress, 3*1000
+		jobs = _.map ids, (id)->
+			return (cb)->
+				processNext(id, cb)
+		async.series jobs, (err)->
+			if err?
+				console.error err, "at end of jobs"
+			else
+				console.log "finished"
+			clearInterval interval
+			done(err)
+
+exports.rollback = (client, done)->
+	done()
+
+DAYS = 24 * 3600 * 1000 # one day in milliseconds
+
+# copied from track-changes/app/coffee/PackManager.coffee
+
+PackManager =
+	MAX_SIZE:  1024*1024 # make these configurable parameters
+	MAX_COUNT: 512
+
+	convertDocsToPacks: (docs, callback) ->
+		packs = []
+		top = null
+		docs.forEach (d,i) ->
+			# skip existing packs
+			if d.pack?
+				top = null
+				return
+			sz = BSON.calculateObjectSize(d)
+			# decide if this doc can be added to the current pack
+			validLength = top? && (top.pack.length < PackManager.MAX_COUNT)
+			validSize = top? && (top.sz + sz < PackManager.MAX_SIZE)
+			bothPermanent = top? && (top.expiresAt? is false) && (d.expiresAt? is false)
+			bothTemporary = top? && (top.expiresAt? is true) && (d.expiresAt? is true)
+			within1Day = bothTemporary && (d.meta.start_ts - top.meta.start_ts < 24 * 3600 * 1000)
+			if top? && validLength && validSize && (bothPermanent || (bothTemporary && within1Day))
+				top.pack = top.pack.concat {v: d.v, meta: d.meta,  op: d.op, _id: d._id}
+				top.sz += sz
+				top.n += 1
+				top.v_end = d.v
+				top.meta.end_ts = d.meta.end_ts
+				top.expiresAt = d.expiresAt if top.expiresAt?
+				return
+			else
+				# create a new pack
+				top = _.clone(d)
+				top.pack = [ {v: d.v, meta: d.meta,  op: d.op, _id: d._id} ]
+				top.meta = { start_ts: d.meta.start_ts, end_ts: d.meta.end_ts }
+				top.sz = sz
+				top.n = 1
+				top.v_end = d.v
+				delete top.op
+				delete top._id
+				packs.push top
+
+		callback(null, packs)
+
+	checkHistory: (docs, callback) ->
+		errors = []
+		prev = null
+		error = (args...) ->
+			errors.push args
+		docs.forEach (d,i) ->
+			if d.pack?
+				n = d.pack.length
+				last = d.pack[n-1]
+				error('bad pack v_end', d) if d.v_end != last.v
+				error('bad pack start_ts', d) if d.meta.start_ts != d.pack[0].meta.start_ts
+				error('bad pack end_ts', d) if d.meta.end_ts != last.meta.end_ts
+				d.pack.forEach (p, i) ->
+					prev = v
+					v = p.v
+					error('bad version', v, 'in', p) if v <= prev
+					#error('expired op', p, 'in pack') if p.expiresAt?
+			else
+				prev = v
+				v = d.v
+				error('bad version', v, 'in', d) if v <= prev
+		if errors.length
+			callback(errors)
+		else
+			callback()
+
+	insertPack: (packObj, callback) ->
+		bulk = db.docHistory.initializeOrderedBulkOp()
+		doc_id = packObj.doc_id
+		expect_nInserted = 1
+		expect_nRemoved = packObj.pack.length
+		logger.log {doc_id: doc_id}, "adding pack, removing #{expect_nRemoved} ops"
+		bulk.insert packObj
+		ids = (op._id for op in packObj.pack)
+		bulk.find({_id:{$in:ids}}).remove()
+		bulk.execute (err, result) ->
+			if err?
+				logger.error {doc_id: doc_id}, "error adding pack"
+				callback(err, result)
+			else if result.nInserted != expect_nInserted or result.nRemoved != expect_nRemoved
+				logger.error {doc_id: doc_id, result}, "unexpected result adding pack"
+				callback(new Error(
+					msg: 'unexpected result'
+					expected: {expect_nInserted, expect_nRemoved}
+				), result)
+			else
+				db.docHistoryStats.update {doc_id:doc_id}, {
+					$inc:{update_count:-expect_nRemoved},
+					$currentDate:{last_packed:true}
+				}, {upsert:true}, () ->
+					callback(err, result)
+
+	# retrieve document ops/packs and check them
+	getDocHistory: (doc_id, callback) ->
+		db.docHistory.find({doc_id:ObjectId(doc_id)}).sort {v:1}, (err, docs) ->
+			return callback(err) if err?
+			# for safety, do a consistency check of the history
+			logger.log {doc_id}, "checking history for document"
+			PackManager.checkHistory docs, (err) ->
+				return callback(err) if err?
+				callback(err, docs)
+				#PackManager.deleteExpiredPackOps docs, (err) ->
+				#	return callback(err) if err?
+				#	callback err, docs
+
+	packDocHistory: (doc_id, options, callback) ->
+		if typeof callback == "undefined" and typeof options == 'function'
+			callback = options
+			options = {}
+		LockManager.runWithLock(
+			"HistoryLock:#{doc_id}",
+			(releaseLock) ->
+				PackManager._packDocHistory(doc_id, options, releaseLock)
+			,	callback
+		)
+
+	_packDocHistory: (doc_id, options, callback) ->
+		logger.log {doc_id},"starting pack operation for document history"
+
+		PackManager.getDocHistory doc_id, (err, docs) ->
+			return callback(err) if err?
+			origDocs = 0
+			origPacks = 0
+			for d in docs
+				if d.pack? then	origPacks++	else origDocs++
+			PackManager.convertDocsToPacks docs, (err, packs) ->
+				return callback(err) if err?
+				total = 0
+				for p in packs
+					total = total + p.pack.length
+				logger.log {doc_id, origDocs, origPacks, newPacks: packs.length, totalOps: total}, "document stats"
+				if packs.length
+					if options['dry-run']
+						logger.log {doc_id}, 'dry-run, skipping write packs'
+						return callback()
+					PackManager.savePacks packs, (err) ->
+						return callback(err) if err?
+						# check the history again
+						PackManager.getDocHistory doc_id, callback
+				else
+					logger.log {doc_id}, "no packs to write"
+					# keep a record that we checked this one to avoid rechecking it
+					db.docHistoryStats.update {doc_id:doc_id}, {
+						$currentDate:{last_checked:true}
+					}, {upsert:true}, () ->
+						callback null, null
+
+	DB_WRITE_DELAY: 100
+
+	savePacks: (packs, callback) ->
+		async.eachSeries packs, PackManager.safeInsert, (err, result) ->
+			if err?
+				logger.log {err, result}, "error writing packs"
+				callback err, result
+			else
+				callback()
+
+	safeInsert: (packObj, callback) ->
+		PackManager.insertPack packObj, (err, result) ->
+			setTimeout () ->
+				callback(err,result)
+			, PackManager.DB_WRITE_DELAY
+
+	deleteExpiredPackOps: (docs, callback) ->
+		now = Date.now()
+		toRemove = []
+		toUpdate = []
+		docs.forEach (d,i) ->
+			if d.pack?
+				newPack = d.pack.filter (op) ->
+					if op.expiresAt? then op.expiresAt > now else true
+				if newPack.length == 0
+					toRemove.push d
+				else if newPack.length < d.pack.length
+					# adjust the pack properties
+					d.pack = newPack
+					first = d.pack[0]
+					last = d.pack[d.pack.length - 1]
+					d.v_end = last.v
+					d.meta.start_ts = first.meta.start_ts
+					d.meta.end_ts = last.meta.end_ts
+					toUpdate.push d
+		if toRemove.length or toUpdate.length
+			bulk = db.docHistory.initializeOrderedBulkOp()
+			toRemove.forEach (pack) ->
+				console.log "would remove", pack
+				#bulk.find({_id:pack._id}).removeOne()
+			toUpdate.forEach (pack) ->
+				console.log "would update", pack
+				#bulk.find({_id:pack._id}).updateOne(pack);
+			bulk.execute callback
+		else
+			callback()