Curiosity: Is Pattern Data compressed?

[Saga Musix]

That's probably going to be the least important thing at all, but I have no intention to change it.

[Kitsune_Phoenix]

That could be a little confusing. Granted, file extensions don't actually matter with OpenMPT, but older versions would only recognize the older format (MPTM), so if they tried to open an MPTM that was actually in the newer format, it could cause problems. You could show an error message, like "This MPTM was written using a newer version of OpenMPT and cannot be opened."

But if you are like me and play a lot of Metroid, you could be a bit more creative and say something like "Analysis inconclusive. Module incompatible with current tracker."

Back on topic, I think MPX would or MPTX would be enough of a distinction so that people don't accidentally try to open them in older versions of OpenMPT.

[Saga Musix]

If people really open it with an older version, they will notice that they cannot open it. Just as if they saw a different extension. Actually, using the same extension would have the benefit of them seeing that the file might indeed be open-able by OpenMPT, but their version is too old.

[arseniiv]

You could show an error message, like "This MPTM was written using a newer version of OpenMPT and cannot be opened."

But, erm, such a change in some version still wouldn't change all the previous ones—and there's no guarantee the older aren't in use at any future date. They would still behave old way, so what's the point?

[Saga Musix]

Exactly, OpenMPT cannot predict the future's new magical file format. In fact, it actually shows this exact warning already if an MPTM following the current specifications has a higher internal version number than the current one, but obviously this is not going to work for a completely new, unknown format. Hence, the effect is the same, no matter if you change the extension or not. File extensions are overrated anyway. OpenMPT doesn't need them.