Preliminary table of the SUM of the features added in each game update.

A few particular features worth mentioning:

2.1 Customization Achievements
3.2 Shifting fixed
3.5 Daily Rewards

3.6
Faster in banking
43 cars at once at the track
Warn before using cellular data

3.7 3 Patches released (big mess)

4.0
Increased Team rewards
Team Search, Team goals
Ads for car delivery, service and upgrade

4.2 More ads available
4.4 Time Trials reset

4.5
New: Exclusive Series
New: Full Upgrade Bonuses
First LTS for an old car -- win the Samsung exclusive livery