Boeing 737 differences training

[Johnny Tightlips]

Hi folks, I am lead to believe that when you complete a type rating on any 737 from the 300-900 you have one type rating to fly all of them. If you want to change from say the -800 to a -500 or vice versa, what training would be involved and how long would it take? Also would a -200 pilot have to do a full type rating course to change to the later models or could they complete an abbreviated course? Thanks

[AltFlaps]

In the UK:

The B737 300-900 is a common type rating.
Operators will have an approved course to switch between classics (300/400/500) and NGs (600/700/800/900/BBJ). I understand that it's just a sim session or two and maybe a classroom day.

The Boing 200 series is a completely different type rating