Can't join friends server- don't have the correct modpacks-

[spankadoodle]

I tried to join my friends new voltz server but i couldn't get in because i "didn't have the following modpacks (lists a bunch from voltz)." Some of my friends mods are older than mine. i think because he is using the recommended build, but i am using the latest buyild. the problem is i can't change the build because i am using the new launcher (the new launcher only works on my mac, i always get "update failed, when trying to run voltz. tried everything to fix on the other launcher.) my friend uses the new launcher too.

Any help would be greatly appreciated. :)