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* Use SOFA conventions of version 2.1 from https://github.com/pyfar/sofa_conventions
* Verify SOFA data against all rules defined in the SOFA standard AES69-2022
* Add `Sofa.upgrade_convention` for upgrading outdated conventions. This now uses explicit upgrade rules from https://github.com/pyfar/sofa_conventions
* Remove upgrade functionality from `Sofa.verify`, `sofar.write_sofa`, and `sofar.read_sofa` for a more clear separation of functionality
* Add `Sofa.add_missing` to add missing default data to a SOFA object using the default values specified by the SOFA convention
* Add default parameter value to `Sofa.info`
* Make `sofar.update_conventions` a public function again
* Improve documentation and verbosity of command line output
* Add private function to check congruency of conventions stored as part of SOFAtoolbox and on sofaconventions.org
* Move to Circle CI and improve testing