Spell icons now use players heads instead of vanilla items, when not using the resource pack. The previous RP is still available, use /mexample add vanilla if you need it back.
The spell hotbar in 1.20 uses the "space" provider instead of glyph hacks
Resource pack functionality will be disabled when ItemsAdder is present Use /mconfig configure config override_resource_pack_plugins true to override ItemsAdder
ADDITIONS
Add mount_restricted spell parameter, to disallow certain spells while on a mount
FIXES
Change entity spawning to work around issues with 1.20.x internal changes