Published v.4

Embermage: Death's Bounty tier 10 level requirement wrong (30, should be 53)
Outlander: Repulsion Hex would occasionally get "stuck" so it was always active
Outlander: Rune Vault rank 14 wasn't applying its tier bonus
magic cannon drops didn't have a chance to upgrade to uniques
"of Warming" item affix was reducing electric damage instead of ice

rings, amulets, and studs don't play drop sound twice
pet collars sound more like belts than rings

restore the missing banner welcoming you to Act IV
fix a typo in the main Act IV quest

modifies the following:
\media\layouts\act4_town\1x1single_room_a\act4_town_lm_a.layout
\media\affixes\items\trinket_icepercent_defense5.dat
\media\affixes\skills\repulsion.dat
\media\quests\tl2mainquest\act4\a4-intro_to_act4.dat
\media\skills\arbiter\rejuvenatingkill\rejuvenatingkill.dat
\media\skills\wanderer\phantomflip\phantombackflip.dat
\media\spawnclasses\cannon_magic_spawn.dat
\media\units\items\tl2armor\basearmor_amulet.dat
\media\units\items\tl2armor\basearmor_collar.dat
\media\units\items\tl2armor\basearmor_collar_magic.dat
\media\units\items\tl2armor\basearmor_ring.dat
\media\units\items\tl2armor\basearmor_stud.dat
\media\units\items\tl2armor\basearmor_stud_magic.dat

note to modders:
Please add this to your compilations—as a bugfix, no attribution is necessary. You're also invited to join in the effort by submitting your own minor fixes and I'll add you as a contributor.

Act IV banner: to fix this manually (for compatibility with other mods that modify the same file) simply edit \MEDIA\LAYOUTS\ACT4_TOWN\1X1SINGLE_ROOM_A\ACT4_TOWN_LM_A.LAYOUT with a text editor and replace A1-SHOW_TEXT with A4-SHOWACT4INTRO.