I'm posting a version of this with a few tweaks I thought were needed. This is based on the original version, not the powerplay one (that powerplay bug is just annoying and I believe the uber doesn't even apply on round end).
cvar, which sets which kind of takedamage immune players receive (0 for godmode, 1 for buddha, 2 is normal damage, don't know what the rest are). You can change this at any time and players *should* automatically receive the updated takedamage property if they've got the old takedamage property on them.
" admin override
has replaced the bri_charadminflag cvar, which no longer exists. This is now how you give access to bonus round immunity, and defaults to the reserved flag.
The plugin will only override takedamage if the current takedamage value of the client matches their immunity status (that is, I will only get my takedamage changed to <immunity value> if my takedamage is 2 at the time of the check for adding immunity, and I will only get my takedamage changed back to 2 if my takedamage is <immunity value> at the time of the check for removing immunity).
Let me know how it works.