SRB2 v2.2 is out! Please check out the new 2.2 thread here: https://srb2skybase.org/mb/showthread.php?t=4237

Original post
Current SRB2 version: 2.1.25. This version patch of SRB2 was released on August 17, 2019.

Official downloads page: https://www.srb2.org/download/

Try the 64-bit versions first if you're unsure of which to download. If it doesn't work, fall back to 32-bit. Most computers nowadays should be capable of running 64-bit.

Version 2.1.25 full game installers: 64-bit | 32-bit
Version 2.1.25 full game installers mirrors: 64-bit | 32-bit

Upgrade to v2.1.25 patch (only usable to upgrade from versions 2.1.15 and above): 64-bit | 32-bit
Upgrade to v2.1.25 patch (only usable to upgrade from versions 2.1.15 and above) mirrors: 64-bit | 32-bit

MD5 Hashes
Full game installers:
64-bit MD5: C847FC10CCC191AA8B1C8E4ABD709423
32-bit MD5: BD0B555B18C417AA942A5FBAE7F6E07F

Patches:
64-bit MD5: B77101F3D8663180B8D172D930CFE379
32-bit MD5: DA90B22C4F3A8A5D1CA6A1A70BA75B84

Go nuts!