The formula for calculating player level was changed and this involved changes in several other areas.

Branding/Breeding: Level 7
Horse Skills access: Level 8
Shop Access: Level 9
Barn Access: Level 12
Getting jobs from other players: Level 15
Ranch access: Level 15
Becoming a manufacturer: Level 30
Becoming an equilibrium: Level 40
Becoming a trainer: Level 50

The levels for the magic rewards have changed as well:
The default magic rewards now come at levels 7, 10, 14 and 18.
Between level 21 and 99 the magic rewards come every 7 levels (so 21, 28...63, 70, 77...)
Between 100 and 199 they come every 6 levels (102, 108, ..., 180...198)
200-299 every 5 levels.
300-399 every 4 levels.
400-499 every 3 levels.
500-599 every 2 levels.
600+ for each level.

Most of these things will be explained in greater detail in the wiki.
New player level conversion

Players above level 50 will not be able to enter the automatic shows (it used to be level 200).
The formula for maximum xp added by riders (in the barn) changed to Skill*Level*40.
So a level 50 player with xp skill at 100% will have a 100*50*40 daily limit.