[davvid]

Curious, where did you read the backwards compatibility disclaimer? I couldn't find it, but did find this note:

> The different versions are completely compatible, PCF files are exchangeable between Windows/Linux/*nix/macOS systems.

[anderskaseorg]

At the “About” link http://schnaader.info/precomp.php: “Precomp is not backwards compatible. If you want to recompress some PCF file made with a different version of Precomp, you'll have to use the binaries of the older versions”.