I remember when jQuery 1.4 came out, there was a upgrade link and text where it said that there where stuff that was changed, and stuff we had to rewrite for it to work in 1
For anyone "these days" that is needing help with this, as I just did, it seems that the jQuery team created a better jQuery Migrate plugin that will allow some of the old deprecated code to still work in newer versions (1.9+) of jQuery. As well, if you get the uncompressed version of it, you can use it to pinpoint and debug your older code against the newer version. Works great, so I hope it helps someone else out!
Compressed version of jQuery Migrate plugin
Uncompressed version of jQuery Migrate plugin
I had some really old 1.3.2 code that stopped working when I upgraded to 1.10+, and this allowed it to continue to work without any issues, meanwhile also allowing me to pinpoint the exact code that I needed to rewrite.