Theoretically, the version "number" in this case is technically not a number, because you wouldn't do any math operations with it, it's more like a string. So 3.1415926535897932384626433832795 and 3.14159265358979323846264338327950 are two different strings.

Practically, since TeX will have no new features as they only fix bugs now and the last bugfix release 3.14159265 was 7 years ago, I think we'll actually never get there.

Given that last version is 3.14159265 he certainly isn't worried in hitting 0 anytime soon.

3.1415926535 8979323846 2643383279 50

3.14159265358979323846264338327950...

So not for a while