APRS (packet radio) – FM wide or FM narrow?

Looking at many how-to guides for the Anytone AT-D878UV / AT-D578UV and APRS, it can be hard to determine if APRS should be transmitted as FM (20 kHz bandwidth) or FM narrow (12 kHz bandwidth). Some guides show WIDE while others show NARROW.

The answer is clear in the IARU region 1 VHF band plan – APRS on 144.800 MHz should be transmitted using FM narrow.