Around a year ago, using Fpcupdeluxe, I installed a so called "Fpc 3.3.1" version. Maybe an alias for trunk version. So, in a year, was "3.3.1" improved on bugs fixed?
Yes, it is an alias for trunk, or "git main branch".
Yes, there were fixes within this year. (No I don't have the list / see git log)
But also, there were new bugs within this year.
Some of those new bugs may have also already been fixed, some may have been reported but aren't fixed, and some may not even be known.
3.3.1 / trunk changes all the time. And the amount of bugs in it goes up and down all the time. And as the discovery of each such bug usually takes some time (if they were known immediately, they wouldn't be pushed to git) which can be days but also can be many months, there is no telling how many bugs there currently are.
There may well be long periods with no significant new bugs, or there may be sudden rushes of lots of them, or there may be just a few over a long time... It's hard to tell. Usually, even for those bugs reported and fix, there are no statistics of the exact time they were added, or how long they were in the code base...
Also, those bugs are usually not too obvious. If they break the compiler or its test cases, then they wont live long. But that means, if you compile your app, it likely works... at first. It may be some time until you find the issue.
Of course, its also possible to be on the lucky site, and everything works for you.
Is there some bug list sorted by o.s, Windows, Linux, ecc.? With this, one could decide to risk using "3.3.1", or stop on 3.2.2
Only the official issue tracker. But as above, it wont be complete for todays 3.3.1.
Of course you can select your grace period. I.e. if you set the risk factor at 6 month, after which if a bug has not been reported, then there either isn't one, or you are considering it not a risk to your work. Then you can check a combination of git log and issue tracker. Select a commit 6 month prior to the last bug report you consider an issue for you, then cherry pick any fixes that have been done since and may affect you.