UpdateFound this posted by a Last.fm staff member on the Last.fm forum.
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Staff
9 Nov 2012, 03:11
Radio API update
In March 2009 we released a fully documented and supported radio API. At the time we said that we were going to turn off the old, undocumented and unsupported API within "weeks". For a number of reasons weeks turned into years but we have now seen the vast majority of our radio traffic move off the old API onto the new one. Due to the complexity and costs of supporting multiple versions of the API we have decided that the costs of maintaining the old API now outweigh the benefits of keeping it around for a minority of users and therefore we plan to turn if off on December 1 2012. This means that any old applications or libraries still using the previous API will no longer be able to stream radio from Last.fm unless they are updated to use the new API. Please note that only subscribers are allowed to stream radio via the API - we need the money to cover the associated royalty costs.
More information on the radio API is here:
http://www.last.fm/api/radioWe are trying to contact the developers of applications directly but many of these applications are also old and unsupported and don't properly identify themselves when calling our API so it's not easy to track them all down. If anyone has any questions or comments or needs more information, let us know.