Adaptive Multi-Rate (AMR) Filename extension .amr, .3ga Internet media type audio/amr, audio/3gpp, audio/3gpp2 Initial release 23 June 1999 (1999-06-23)[1][2] Latest release 14.0.0 (17 March 2017; 2 years ago (2017-03-17)) Type of format Audio compression format, audio file format