On https://www.phpbb.com/
one sees

Try our Demo | Download 3.1.8 2016-2-23

1. Please also put the version number on the Demo:

Try our Demo 3.1.5 | Download 3.1.8 2016-2-23

2. Doing so would insure the user was aware of the very important difference!

3. Also it would make sense for the demo to please be automatically
updated to match the release listed to the right of it.

In fact, if one offered a newer demo that the download to the right of
it, one would be criticized for delivering an older model than what was
in the test drive. Just the same the other way around too!