They mention one reason in the release notes:
> unintended SSE CPU requirement present in previous releases has been removed.
> unintended SSE CPU requirement present in previous releases has been removed.
What did they do feature-wise in newer versions that makes the old versions desirable to some people, to the point that a user would prefer to upgrade them rather than upgrade to the newest version? It's not about system compatibility: the 2.x line supports Windows all the way back to Windows 7.
I'm content to dig into the docs but I was wondering about people's personal experiences with it. One hint in the release notes is that some, but not all, old plugins work in the new version...
1.6 is the last version before the big rework.
I wouldn't be surprised if a decent amout of people were still running Windows XP, esp. on old hardware.