[Paul M]

Its simply a 10 char field (in the database) and has been since the day it was created (however many years ago now).
It appears in several tables and tbh, its not really likely to be changed anytime soon.

Ive just started to use a new system : "1.2.3.x" where 1.2.3 corresponds to the vb version it was initially written (or updated) for, and x just starts at 0 and increments (including for beta versions). If the next release comes after a new vb versions has been released, we start again.

e.g.

4.1.7.0 - first version for vb 4.1.7 (beta)
4.1.7.1 - first update, still for vb 4.1.7 (still beta)
4.1.7.2 - next update, still for vb 4.1.7 (no longer beta)
4.1.8.0 - first update after vb 4.1.8 released.
4.1.8.1 - next update, still for vb 4.1.8

I suppose you could use 4.1.7.b1, not sure how the plugin system would respond to that.