+1
To explain:
We have the major version
Pharo2 Pharo3 Pharo4
These are released once per year.
While developing, we do updates. At some point (e.g. #553) we release. Then we continue to do do updates.
So Pharo images are always 100% identifiable by Major+UpdateNumber.
When you go to pharo.org, you download the *latest* update. Else we end up getting bug reports for already fixed issues constantly (this happend now already multiple times, and I feel to bad that someone takes such a huge effort to report a bug that we fixed weeks ago).
If you want to re-download the version you go weeks ago, there is
http://files.pharo.org/image/20/
with a complete history, and it is very easy to download exactly what you downloaded weeks ago, yet all the new people get the newest download.
Marcus