As pointed out elsewhere, Microsoft ended support for Windows 7 in 2020. We continued to support it with our latest releases until the 12.2 release in December, 2020. Although 12.2 didn't officially support Windows 7, it didn't actively break anything (that we knew of), but 12.3, released in May of 2021, did.
The decision to drop support wasn't arbitrary. We had long delayed a significant update to our 2D rendering and font rendering subsystems under Windows. We need to replace the legacy GDI-based systems with modern DirectWrite-based systems. DirectWrite first shipped with Windows 7, but it wasn't yet in a fully baked state in that initial release. We did as much as we could by elevating the minimum OS to Windows 7 Platform Update in 12.0. But we couldn't completely eradicate our GDI usage without using DirectWrite as it stood in Windows 8.1 (which basically nobody uses anymore, so we just went to Windows 10).
Eradicating GDI was important not only to allow new feature development, but because some of our GDI usage was being actively flagged by some AV/security software in the wild. This had been reported to us dozens, if not hundreds of times, so fixing it was a huge priority. Our usage of GDI was perfectly supported by Microsoft, and caused no security problems. But the world changed around us, and some modern security vendors were willing to conclude that anyone using certain GDI techniques posed a potential threat, without the need to verify whether the threat was real.
And, yes, Microsoft's dropping support, and feedback from our sales and support teams made it seem like the sting wouldn't be too bad as well. I'm certainly very sorry that this affects you the way it has, but I'm also extremely happy that we can tell people who were having their usage of our products blocked by their security software that they can now update rather than crafting security exceptions (an option which, rightly, some folks weren't so happy with). And this unblocks some of our development on high performance drawing, better HiDpi support, and support of fast-evolving font technology.
