Reviewed by me a year ago here, before the demise of the Nokia Store (in terms of updates or anything new), the 'pro' music player QuasarMX has been given a new lease of life by the developer, with a download path for the free version and an upgrade, license-transferring path for the paid version. See below for some quotes and links.

From my review intro:

However, real music afficionados might want to go further. Fancy gapless playback? Fancy playing back Ogg Vorbis and FLAC files as well? Fancy integrated, fully working cover art, lyrics, and artist bio downloading? Fancy a full 10 band parametric EQ with additional bass and treble customisations? Fancy comprehensive genre-based playlist construction? You'll be wanting QuasarMX then. 

From the developer post:

You may have read that upgrades via the Nokia/Ovi store are no longer possible.

For users of the Lite version of QuasarMX: Just uninstall the old version and download and install the free version.

For owners of the Full version of QuasarMX (now Pro) this unfortunately means that upgrading is a bit more involving because we do not have any record of who has bought the full version from Nokia. For a proof of ownership the new version of QuasarMX will scan your device for an older installed full version of QuasarMX.

Here are the upgrade steps for the Full/Pro version:

1. Make sure you have the latest version of QuasarMX Full installed from the Nokia/Ovi store:
2. Install the free version of QuasarMX from our website:

   Download QuasarMX free version

3. Start the free version of QuasarMX (notice the new icon).

   

4. The app will tell you that it has found an installed version of QuasarMX Full on your device. Please follow the instructions on the screen to create an account or login with an existing account. The license will be transferred to your account. Once this is done, you may either unlock the Pro features immediately in the app or download and install the package of the Pro version.
5. You may now uninstall the old version of QuasarMX.

If you previously skipped the upgrade check, you can easily start the upgrade again via Main Menu > Help & About> Unlock Pro features.

It's all worth it - I was very impressed by QuasarMX on Symbian:

Any problems with the update/upgrade, just see the developer's home page here. Any comments on QuasarMX in your life, a year on?