An Asterisk administrator discusses upgrading an Asterisk PBX from version 11 to version 16. This involved building new Debian packages, porting configurations, updating dialplans, testing features, and addressing issues like crashes, logging problems, and high system loads. Through testing and troubleshooting, the upgrade was eventually successful and the system could handle the same call load as the previous version. However, ongoing work is still needed to optimize logging and reduce continuous CPU loads.