diff --git a/src/Connector.js b/src/Connector.js
index b0f6c65c..b6d1f3f5 100644
--- a/src/Connector.js
+++ b/src/Connector.js
@@ -29,6 +29,7 @@ export default class AbstractConnector {
     this.currentSyncTarget = null
     this.debug = opts.debug === true
     this.broadcastBuffer = new BinaryEncoder()
+    this.broadcastBufferSize = 0
     this.protocolVersion = 11
     this.authInfo = opts.auth || null
     this.checkAuth = opts.checkAuth || function () { return Promise.resolve('write') } // default is everyone has write access
@@ -160,22 +161,29 @@ export default class AbstractConnector {
     if (firstContent) {
       this.broadcastBuffer.writeVarString(this.y.room)
       this.broadcastBuffer.writeVarString('update')
+      this.broadcastBufferSize = 0
+      this.broadcastBufferSizePos = this.broadcastBuffer.pos
+      this.broadcastBuffer.writeUint32(0)
     }
+    this.broadcastBufferSize++
     struct._toBinary(this.broadcastBuffer)
     if (this.maxBufferLength > 0 && this.broadcastBuffer.length > this.maxBufferLength) {
       // it is necessary to send the buffer now
       // cache the buffer and check if server is responsive
-      let buffer = this.broadcastBuffer
+      const buffer = this.broadcastBuffer
+      buffer.setUint32(this.broadcastBufferSizePos, this.broadcastBufferSize)
       this.broadcastBuffer = new BinaryEncoder()
       this.whenRemoteResponsive().then(() => {
-        this.broadcast(buffer)
+        this.broadcast(buffer.createBuffer)
       })
     } else if (firstContent) {
       // send the buffer when all transactions are finished
       // (or buffer exceeds maxBufferLength)
       setTimeout(() => {
         if (this.broadcastBuffer.length > 0) {
-          this.broadcast(this.broadcastBuffer.createBuffer())
+          const buffer = this.broadcastBuffer
+          buffer.setUint32(this.broadcastBufferSizePos, this.broadcastBufferSize)
+          this.broadcast(buffer.createBuffer())
           this.broadcastBuffer = new BinaryEncoder()
         }
       }, 0)
diff --git a/src/MessageHandler/integrateRemoteStructs.js b/src/MessageHandler/integrateRemoteStructs.js
index 8f6a7df8..d561b65e 100644
--- a/src/MessageHandler/integrateRemoteStructs.js
+++ b/src/MessageHandler/integrateRemoteStructs.js
@@ -47,7 +47,8 @@ function _integrateRemoteStructHelper (y, struct) {
 }
 
 export function stringifyStructs (y, decoder, strBuilder) {
-  while (decoder.length !== decoder.pos) {
+  const len = decoder.readUint32()
+  for (let i = 0; i < len; i++) {
     let reference = decoder.readVarUint()
     let Constr = getStruct(reference)
     let struct = new Constr()
@@ -61,7 +62,8 @@ export function stringifyStructs (y, decoder, strBuilder) {
 }
 
 export function integrateRemoteStructs (decoder, encoder, y) {
-  while (decoder.length !== decoder.pos) {
+  const len = decoder.readUint32()
+  for (let i = 0; i < len; i++) {
     let reference = decoder.readVarUint()
     let Constr = getStruct(reference)
     let struct = new Constr()
diff --git a/src/MessageHandler/syncStep1.js b/src/MessageHandler/syncStep1.js
index 3992862a..4f081339 100644
--- a/src/MessageHandler/syncStep1.js
+++ b/src/MessageHandler/syncStep1.js
@@ -31,14 +31,19 @@ export function sendSyncStep1 (connector, syncUser) {
 }
 
 export default function writeStructs (encoder, decoder, y, ss) {
+  const lenPos = encoder.pos
+  encoder.writeUint32(0)
+  let len = 0
   for (let user of y.ss.state.keys()) {
     let clock = ss.get(user) || 0
     if (user !== RootFakeUserID) {
       y.os.iterate(new ID(user, clock), new ID(user, Number.MAX_VALUE), function (struct) {
         struct._toBinary(encoder)
+        len++
       })
     }
   }
+  encoder.setUint32(lenPos, len)
 }
 
 export function readSyncStep1 (decoder, encoder, y, senderConn, sender) {
@@ -54,9 +59,9 @@ export function readSyncStep1 (decoder, encoder, y, senderConn, sender) {
   // write sync step 2
   encoder.writeVarString('sync step 2')
   encoder.writeVarString(y.connector.authInfo || '')
-  writeDeleteSet(y, encoder)
   const ss = readStateSet(decoder)
   writeStructs(encoder, decoder, y, ss)
+  writeDeleteSet(y, encoder)
   y.connector.send(senderConn.uid, encoder.createBuffer())
   senderConn.receivedSyncStep2 = true
   if (y.connector.role === 'slave') {
diff --git a/src/MessageHandler/syncStep2.js b/src/MessageHandler/syncStep2.js
index a8dc4208..a169073b 100644
--- a/src/MessageHandler/syncStep2.js
+++ b/src/MessageHandler/syncStep2.js
@@ -3,6 +3,8 @@ import { readDeleteSet } from './deleteSet.js'
 
 export function stringifySyncStep2 (y, decoder, strBuilder) {
   strBuilder.push('     - auth: ' + decoder.readVarString())
+  strBuilder.push('  == OS:')
+  stringifyStructs(y, decoder, strBuilder)
   // write DS to string
   strBuilder.push('  == DS:')
   let len = decoder.readUint32()
@@ -17,12 +19,10 @@ export function stringifySyncStep2 (y, decoder, strBuilder) {
       strBuilder.push(`[${from}, ${to}, ${gc}]`)
     }
   }
-  strBuilder.push('  == OS:')
-  stringifyStructs(y, decoder, strBuilder)
 }
 
 export function readSyncStep2 (decoder, encoder, y, senderConn, sender) {
-  readDeleteSet(y, decoder)
   integrateRemoteStructs(decoder, encoder, y)
+  readDeleteSet(y, decoder)
   y.connector._setSyncedWith(sender)
 }
diff --git a/src/Struct/Delete.js b/src/Struct/Delete.js
index ecfc717b..e750c04c 100644
--- a/src/Struct/Delete.js
+++ b/src/Struct/Delete.js
@@ -1,5 +1,6 @@
 import { getReference } from '../Util/structReferences.js'
 import ID from '../Util/ID.js'
+import { logID } from '../MessageHandler/messageToString.js'
 
 /**
  * Delete all items in an ID-range
@@ -42,6 +43,8 @@ export default class Delete {
     this._length = null
   }
   _fromBinary (y, decoder) {
+    // TODO: set target, and add it to missing if not found
+    // There is an edge case in p2p networks!
     this._targetID = decoder.readID()
     this._length = decoder.readVarUint()
     return []
@@ -71,6 +74,6 @@ export default class Delete {
     }
   }
   _logString () {
-    return `Delete - target: ${this._target}, len: ${this._length}`
+    return `Delete - target: ${logID(this._targetID)}, len: ${this._length}`
   }
 }
diff --git a/src/Struct/Item.js b/src/Struct/Item.js
index 49249579..a430b5ef 100644
--- a/src/Struct/Item.js
+++ b/src/Struct/Item.js
@@ -297,8 +297,6 @@ export default class Item {
         this._parent = this._origin._parent
       } else if (this._right_origin !== null) {
         this._parent = this._right_origin._parent
-      } else if (missing.length === 0) {
-        debugger
       }
     }
     if (info & 0b1000) {
diff --git a/test/y-array.tests.js b/test/y-array.tests.js
index 2d036842..26647338 100644
--- a/test/y-array.tests.js
+++ b/test/y-array.tests.js
@@ -228,7 +228,7 @@ var arrayTransactions = [
     var pos = chance.integer({ min: 0, max: yarray.length })
     yarray.insert(pos, content)
   },
-  /*function insertTypeArray (t, user, chance) {
+  function insertTypeArray (t, user, chance) {
     const yarray = user.get('array', Y.Array)
     var pos = chance.integer({ min: 0, max: yarray.length })
     yarray.insert(pos, [Y.Array])
@@ -243,7 +243,7 @@ var arrayTransactions = [
     map.set('someprop', 42)
     map.set('someprop', 43)
     map.set('someprop', 44)
-  },*/
+  },
   function _delete (t, user, chance) {
     const yarray = user.get('array', Y.Array)
     var length = yarray.length
diff --git a/tests-lib/helper.js b/tests-lib/helper.js
index cd5b26dc..e70a396f 100644
--- a/tests-lib/helper.js
+++ b/tests-lib/helper.js
@@ -103,7 +103,7 @@ export async function compareUsers (t, users) {
     u.os.iterate(null, null, function (op) {
       const json = {
         id: op._id,
-        left: op._left === null ? null : op._left._id,
+        left: op._left === null ? null : op._left._lastId,
         right: op._right === null ? null : op._right._id,
         length: op._length,
         deleted: op._deleted