It's pretty stupid. With my N8 I can still drag & drop m4a files directly to the phone when connected in PC suite mode. Renaming m4a files to .aac does not work.
As per Nokia Ovi Suite help,
Audio file formats
Nokia Ovi Suite supports the audio file formats listed below. You can play and transfer music files between your device and computer in these formats.
AAC, eAAC, eAAC+,
WMA (all variants), protected by Windows Media DRM.
yeah, we noticed that.
But suffice it to say that we are not talking about file formats, but file extension.
.m4a files are AAC files which are supported by Ovi-suite as you conveniently point out.
But that IS NOT THE POINT.
The now officially worst smartphone desktop software ever has lost the ability to import AAC files with an .m4a extension. By the way .m4a is the standard file extension for songs bough in the iTunes store.
Up to at least version 3.0 Ovi suite was able to add .m4a files ( again, Standard iTunes extiension) with no problem.
But all of a sudden that extension has been removed.
You now have to start Ovi Player to add those files to the library, after that tjhey will play fine in the Ovi Suite as do .m4a files that were added to the library pre-3.1, since they are indeed standard AAC files.
Removing support for one of the more widespread audio file extensions is just one more example of the mind-boggling incompetence of the Ovi-suite developers.
The Suite keeps getting worse and worse instead of less bad. Never has it been more tedious to keep a PDA or smartphone up to date than with the pathetic Ovi-suite. Now I could maybe even live with that if the handsets weren't equally or even more useless (N97).