Hey @arendvw, you’re totally right; this needs to be better supported.
When yak builds the package it inspects it and adds a distribution tag to the filename which is read by the server when publishing. The platform part of this tag is configurable with the --platform <platform> argument, but there isn’t yet an equivalent to override the Rhino version.
The package manager only allows you to install packages that match the minimum Rhino version. There’s also a secondary requirement that major version numbers match. I plan to make this requirement optional but that change will only affect Rhino 7 and above.
I’d suggest either renaming the Rhino version part of the filename to support Rhino 6, e.g. ScriptParasite-1.0.4-rh6_0-any.yak, or you could mark it as being compatible with any version of Rhino, e.g. ScriptParasite-1.0.4-any-any.yak.
By using different distribution tags you can publish different builds of a plug-in multiple times using the same version number.