Upgrade from Ext JS 3.x to Ext JS 4 Beta?

What are the risks associated with upda开发者_如何学Cting from ExtJS 3.x to Ext JS 4 Beta?

Would you expect that user extensions which work with Ext JS 3.x will work with Ext JS 4 Beta?

Would it be as simple as replacing Ext Js 3.x with ExtJs 4?

Should I update or wait until there is an official stable release?

What are the risks associated with updating from ExtJS 3.x to Ext JS 4 Beta?

Ext 4 is not backwards-compatible to Ext 3. Expect to spend significant time upgrading and testing, depending on how large your existing application is. Once you see the impact on your specific app, you'll be able to evaluate your own specific risk. It all depends. There will be migration documentation, so hopefully that will mitigate the risk somewhat.

Would you expect that user extensions which work with Ext JS 3.x will work with Ext JS 4 Beta?

No, not by default. I would expect most will need to be upgraded, but again, it depends on the specific component.

Would it be as simple as replacing Ext Js 3.x with ExtJs 4?

No. You might want to watch this thread on the Sencha forums.

I think this question isn't specific to ext js at all. I think the answer to the same for the following question: "Upgrade from <some library i'm using> to <Beta version of next release for library I'm using>?"

And the answer is a recommended no. Betas for 3rd party libs aren't like betas for websites. They could have major changes by the time the final release comes out and any code you write on top of a beta could become useless. To be honest, the most I would do with a beta release is just try and plug it in to my project to gauge how much work is going to be involved in upgrading once the final release comes out.