# Backward compatibility and Canvas 'data-engine' addition **URL:** \ **Category:** Questions\ **Created:** [December 20, 2021, 8:26pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205 "2021-12-20T20:26:43Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![Leonardo\_Villalobos](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/leonardo_villalobos/32/9628_2.png) [@Leonardo\_Villalobos](https://forum.babylonjs.com/u/Leonardo_Villalobos)\ **Post date:** [December 20, 2021, 8:26pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/1 "2021-12-20T20:26:43Z")
![2021-12-20](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/8/a/8a5a636365b3df27fe87ed0ec9ebfcbf3a11fcfd.jpeg) Have you made the new cdn libraries in such way that a data-engine=“Babylon 5.0xxx” appears as a attribute of the canvas, as it is shown in picture? In case it’s correct, may i knoww why??? If it’s not the case. then what did i do wrong? ---
**Author:** ![sebavan](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/sebavan/32/57_2.png) [@sebavan](https://forum.babylonjs.com/u/sebavan)\ **Post date:** [December 20, 2021, 10:00pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/2 "2021-12-20T22:00:46Z")
It is fully correct and it helps quickly spotting the engine version associated to a canvas in the page. ThreeJS did the same not long ago. This should not break anything that was existing before. ---
**Author:** ![Leonardo\_Villalobos](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/leonardo_villalobos/32/9628_2.png) [@Leonardo\_Villalobos](https://forum.babylonjs.com/u/Leonardo_Villalobos)\ **Post date:** [December 22, 2021, 4:54pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/3 "2021-12-22T16:54:32Z")
![image](https://us1.discourse-cdn.com/flex024/uploads/babylonjs/original/3X/e/9/e9c5eca2a4ddc1ab6889fe95c4f58401e7197302.png) However it does. The image show the error i get when trying to load a 4.2 version of a localhost served babylon files. Any suggerstion? ---
**Author:** ![sebavan](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/sebavan/32/57_2.png) [@sebavan](https://forum.babylonjs.com/u/sebavan)\ **Post date:** [December 22, 2021, 5:19pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/4 "2021-12-22T17:19:41Z")
This has nothing to do with data-engine ??? It looks like you are using a 5.0 alpha version of the materials file with a 4.2 of the engine. Could you repro in the playground ? ---
**Author:** ![Leonardo\_Villalobos](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/leonardo_villalobos/32/9628_2.png) [@Leonardo\_Villalobos](https://forum.babylonjs.com/u/Leonardo_Villalobos)\ **Post date:** [December 22, 2021, 5:33pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/5 "2021-12-22T17:33:21Z")
Oh. Ok. Where can I found the zip file with the 4.2 version complete? Best regards Leo ---
**Author:** ![sebavan](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/sebavan/32/57_2.png) [@sebavan](https://forum.babylonjs.com/u/sebavan)\ **Post date:** [December 22, 2021, 5:36pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/6 "2021-12-22T17:36:12Z")
they are all available here [Babylon.js/dist at master · BabylonJS/Babylon.js · GitHub](https://github.com/BabylonJS/Babylon.js/tree/master/dist) ---
**Author:** ![Leonardo\_Villalobos](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/leonardo_villalobos/32/9628_2.png) [@Leonardo\_Villalobos](https://forum.babylonjs.com/u/Leonardo_Villalobos)\ **Post date:** [December 22, 2021, 5:52pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/7 "2021-12-22T17:52:38Z")
Ok. Give me some minutes to download the files needed, try again and come back to you. Thanks Leo ---
**Author:** ![Leonardo\_Villalobos](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/leonardo_villalobos/32/9628_2.png) [@Leonardo\_Villalobos](https://forum.babylonjs.com/u/Leonardo_Villalobos)\ **Post date:** [December 22, 2021, 6:42pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/8 "2021-12-22T18:42:12Z")
It seems that I have spent time and the work doesn’t run anymore. 😰 No posible to put to work none of the jobs without errors or as it should used to. Bye ---
**Author:** ![sebavan](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/sebavan/32/57_2.png) [@sebavan](https://forum.babylonjs.com/u/sebavan)\ **Post date:** [December 22, 2021, 6:43pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/9 "2021-12-22T18:43:28Z")
I am pretty sure we can help if you provide a repro but it is impossible without seeing the code. ---
**Author:** ![Leonardo\_Villalobos](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/leonardo_villalobos/32/9628_2.png) [@Leonardo\_Villalobos](https://forum.babylonjs.com/u/Leonardo_Villalobos)\ **Post date:** [December 22, 2021, 7:06pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/10 "2021-12-22T19:06:57Z")
Ok. Made it work but not in local file folders, changed to your cdn, and at least it works but too slow since using physics files. My repo is this [http://htmlpreview.github.io/?https://github.com/LeonardoVU/Dev-Games/blob/master/ExplorationTank/OwnJS/Human.html](http://htmlpreview.github.io/?https://github.com/LeonardoVU/Dev-Games/blob/master/ExplorationTank/OwnJS/Human.html) But, js files should not be public. Therefore, obfuscation was applied. Any suggestions? Leo ---
**Author:** ![Deltakosh](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/deltakosh/32/26635_2.png) [@Deltakosh](https://forum.babylonjs.com/u/Deltakosh)\ **Post date:** [January 3, 2022, 3:40pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/11 "2022-01-03T15:40:12Z")
Sorry but what are the remaining issues? You can find the 4.2 js files here: [Babylon.js/dist at master · BabylonJS/Babylon.js (github.com)](https://github.com/BabylonJS/Babylon.js/tree/master/dist) ---
**Author:** ![carolhmj](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/carolhmj/32/25918_2.png) [@carolhmj](https://forum.babylonjs.com/u/carolhmj)\ **Post date:** [February 1, 2022, 11:48am UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/12 "2022-02-01T11:48:02Z")
Hello @Leonardo_Villalobos just checking in if you still have issues. ---
**Author:** ![Leonardo\_Villalobos](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/leonardo_villalobos/32/9628_2.png) [@Leonardo\_Villalobos](https://forum.babylonjs.com/u/Leonardo_Villalobos)\ **Post date:** [February 1, 2022, 3:15pm UTC](https://forum.babylonjs.com/t/backward-compatibility-and-canvas-data-engine-addition/26205/13 "2022-02-01T15:15:26Z")
Hi, Carol. Thanks for asking, but, no. downloaded the preview files and no problems at all. Thxs. bye, Leo