What exactly made it so that old installers do not work anymore?

[Apex6]

The installers for some versions such as #1902 1.8.9 do not work anymore, if you try to launch their jar file it simply won't open and will give you an error.

But what exactly made it so that on 4/20/21 the installers didn't work? Was there an update or anything? And if there was couldn't they just put the old JAR file back?

If this is a java issue, is it possibly fixable by downloading old java?

I think this is very important as the only versions of forge that Optifine runs on 1.8.9, 1902 and 1764, are broken, and if you attempt to use the main version (2318) your game screen will freeze every 5-10 seconds for 1 second.