Users can write ZAP scripts based on Groovy 5.
https://groovy-lang.org/releasenotes/groovy-5.0.html

Upgrading to Groovy 5 will not affect existing scripts. However, this does not apply to the package splitting changes documented in the Groovy 3 release notes: https://groovy-lang.org/releasenotes/groovy-3.0.html#Groovy3.0releasenotes-Splitpackages.