MSG,n type messages on port 30003 are 5-minute delayed. Others, such as AIR, ID, SEL, etc. are real-time (I think).
Squawk is 5-minute delayed - I just wish Airnav had incorporated Squawk Code lookup in v3, but it didn't make it into the final version :( I really miss the ability to get automatic squawk code lookups in real-time, the only backward-step in v3.