Hi Alessio,
The SmartBear Cucumber team prioritises maintenance of Java, TypeScript, Go and Ruby libraries. For other libraries we rely on community contributions.
The Gherkin grammar underwent some changes in v6 - adding a new Rule keyword. There are no grammar changes between v6 and v13, just API changes.
Since no community members have contributed to Gherkin-Python for a while we have disabled releases. When/if someone from the community provides a patch that will make the build for Gherkin-Python build again (and pass all the shared tests), then we will start making new releases.
Cheers,
Aslak