It all depends on the hooks and stuff that a plugin uses, for example 1.9.2 has 'DisplayCommenToolbar' that things like the smilies plugin can hook into, 1.8.x doesn't.

I believe stable means "no major bugs and few minor bugs, but as bugs are only found after release this doesn't mean no bugs" ..... ish

¥

yeah but isn't there a _construct hook in 1.9? has that been backported to 1.8...

Personally I would expect that a 1.9.* plugin would not work in 1.8.* even though probably 80% of them will. Especially if you're thinking of a plugin developed against 1.9.1 and thinking about using it in 1.8.7 for example. My thinking is that most people who write a plugin will use the hooks they need and call it a 1.9.2 plugin because that's the version they were using when they wrote it even though it uses hooks that have existed for a handful of releases.

I'm not sure I understand "backported" but the official releases never change even if CVS is updated for that particular branch.

Stable - to me - means, the amount of confidence Francois has that it's not going to get a zillion bug reports immediately. I guess he takes into account how much has changed and how much of the changed stuff has been tested under how many possible configurations of use. The whole "multi multi multi" thing ya know? For example 1.9.2 is called "stable". I'm guessing that means mostly bug fixes with minor changes that have an extremely low likelyhood of adding new bugs. I haven't used 1.9.* yet because it didn't say "stable" and I got burned with the whole 1.6 thing. Blech. Don't wanna do that again :(