What's the best way to upgrade from jquery 1.3 to 1.4?

Question

I'm trying to decide if upgrading is viable given all the libraries we are using. The problem is some of these plugins arent being developed anymore so I'm not sure which of them is compatible with 1.4

Any thoughts on how to best approach this given legacy dependencies on older plugins?

Answer 1

Trust but verify.

Answer 2

If we were hanging out in #jquery on freenode:

[11:57am] <gnarf> ?tias
[11:57am] <bot-t> Try It And See

Answer 3

If I were approaching this, I would do the following:

• Create a branch or whatever variation on a branch your VCS supports for the change.
• Swap in jQuery 1.4 for jQuery 1.3
• Test extensively to see what breaks - if you have any automated tests, this will be so much the easier
• Depending on what breaks in the legacy packages, see if you can fix it (assuming all plug-ins are open source) or if there is a suitable under-development replacement that supports 1.4
• If any of the plugins are still under development, take this opportunity to upgrade to the latest version (both for 1.4 support and because the latest version likely fixes bugs, etc).
• If you can fix everything you need to fix, merge your changes into the trunk and call your upgrade a success.

Of course, depending on the size and complexity of your code base, this could be a more or less expensive procedure.

EDIT: combined with jvenema's excellent point, you have a nearly fail-safe way to make sure you get to the success point. If something breaks, just throw in the plug-in.

Answer 4

The jQuery guys did a pretty good job of maintaining backwards compatibility where possible, to the point of writing an extension that makes all the 1.3 stuff still work, while getting the performance and features of 1.4.

Check out the details here.