The timezone on your server is probably wrong, it also sounds like you have an older version of the hack as this shouldn't affect the newer versions. Try installing the latest version of the code (2.31).

will this work with 3.5?

No.

The 3.5 version is here ;

https://vborg.vbsupport.ru/showthread.php?t=82769

Good job, installed/

Installed. Works great. Thanks!

Hi, I installed this hack about ten minutes ago, but when I refresh the index page and see that there have been other members online, the new box is blank... and still is! What might be wrong?

Link ?

At a guess, you either haven't done the edit to index.php correctly, or you haven't uploaded the edited file.

What do I need to change to show users from the entire month?

You're joking right ?

Not too bad of an idea for smaller sites.