We running some legacy software on a Server 2000 and VSE 8.8 fails to install on it.
VSE 8.8 Patch 4 is the last release to support installing on Windows 2000.
FYI, should you run into any issues that require a code change to solve, it's not going to happen (because we no longer support that OS).
VSE 8.8 Patch 4 will be fine for DATs and Engine updates so long as we keep producing those types of DAT files (they're called v2 DAT files).
The largest risk you're taking is that our DAT releases are not going to be getting tested anymore on Windows 2000 platform, since it's no longer a supported platform. That means, we don't know what the DATs are going to do on that system - worst case, OS files get detected as malware and deleted and render the box unusable; best case, it's fine and you have current AV protection.
We still have about 10 W2K machines plugging along. (A couple of them won't update from VSE 8.7 to 8.8 despite being SP4; I haven't had the time to investigate why, though.)
Moving forward, we're looking to use Application Control as a means of protecting these old clunkers.
If they are Win2k SP4 without update rollup 1 then that may be the block. Back in the day we stopped rolling UR1 because boxes were blue screening left and right. Luckily they are almost gone.
I knew there was a maximum patch level of VSE88 for Win2K, WWarren confirms a max of patch 4. We ran VSE88 patch 2 with success. So, of course, make sure you're not installing with a patch 5 (or 6) repost.
Also, I can confirm the Update Rollup Pack 1 post an SP4 installation on Win2K. We had one Win2K system that was pre SP4 when we upgraded systems to VSE88 a while back, and I did my homework enough to get SP4 installed prior to installation, but we still had an issue...until I added Update Rollup Pack 1. Should be still available on windows update site.