În ACP - Support I found this message displayed:

Some of the source files for Invision Community have been modified.
/.../.../.../applications/core/setup/upg_107000/upgrade.php
You should download an unmodified copy of those files and upload them to your server. Once that is done, check if the problem persists.

I know for sure that no one has modified any files on my server.

Can someone explain to me, how this problem occurred and why? I need to worry about server security?

Thank you for any explanations!

This is a bug which has been resolved in the latest release of the platform. Please upgrade to the latest release in order to resolve this

Thank you for your prompt answer!

Before posting here, I followed the instructions and downloaded the file from the client area, then uploaded it and now the message is gone. I may encounter problems when I update the software to the latest release?

Thanks!

6 minutes ago, Marius said:

Thank you for your prompt answer!

Before posting here, I followed the instructions and downloaded the file from the client area, then uploaded it and now the message is gone. I may encounter problems when I update the software to the latest release?

Thanks!

No, that wont cause you problems with your upgrade