Asterisk 12 and 13 ship with a a module, res_pjsip_pidf_digium_body_supplement, that is used to pass enhanced Presence information from Asterisk into Digium phones. If you are using a Digium phone with DPMA, this module is necessary. If you are using a Digium phone with the FreePBX REST-ful Phone Apps, this module is necessary. If you are using Digium phones otherwise with Asterisk 12 or 13, there is no need to load this module into Asterisk; if you do so, your phone's line indicator icon will indicate an unknown presence state with a question mark.
For users outside of DPMA and/or the FreePBX REST-ful Phone Apps, this module may be prevented from loading in Asterisk by adding the following line to modules.con in the existing [modules] context, e.g.: