I assume all the changes will come to the classic API at some point.

Until then, supporting both looks like a pain.

Things that need forwards-compatibility wrappers for Classic.

In theory I can test this on live to see if it works without all that hassle of starting classic.

C_Spell

C_Spell.GetSpellInfo
C_Spell.GetSpellSubtext
C_Spell.GetSpellName
C_Spell.IsSpellUsable
C_Spell.GetSpellCooldown

C_MountJournal

C_MountJournal.IsDragonridingUnlocked

Seems to be working now, closing.