Fundamentally, preset wise, v2.12 works like your old 568, v2.5 works like a G6x or recent 861 (post v3.5). That is with v2.5, format decode is largely transparent to the user. Under the bonnet, v2.5 is significantally different to v2.12 as it marks the point when Meridian unified the code with 861 and G series, hence as mentioned above, it inherited some of enhancements, and defects, of the newer processors.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).