In each of the device changelogs, T-Mobile simply lists, “security fixes.” It’s pretty vague, but it’s better than no changelog at all.
Once updated, S8 owners will be on software version G950USQU5DSD3, the S8+ will be on G955USQU5DSC1, and the Note 8 will be on N950USQU5DSD3.
Get on it, Galaxy peeps!
Update: Apparently it’s the April security patch, not May’s. We don’t have an S8 or Note 8 to confirm, but either way, security update! Thanks, Christopher!