As you may have read recently, the venerable MP3 audio format has been declared "officially dead". While this may be true officially it's certainly not true technically - MP3s will be around for a while yet. Podcasts have been one of the last bastions of the MP3 audio format while other net audio has moved over to its successor, AAC.
Over the past year we've begun a transition to AAC with our podcasts (starting with the game recordings), however by the end of 2017 I anticipate that all our net-based audio releases will be in the successor format; it's more efficient and offers better quality (certainly at lower bit rates). Unless your audio player is relatively antique then it should be able to handle the AAC audio format. iTunes for example has used AAC audio for the last 15 years, it can also convert AAC to MP3 if absolutely required.
The switch isn't happening overnight, but by 2018 all new audio from us should be in AAC format. Legacy material will remain as-is - I'm certainly not re-encoding a thousand files!
Anyway just a heads-up for the future.