1.17 and under support was stripped as a part of this commit. The tested minecraft versions and list of supported versions in the descriptions should be updated to reflect the change.
Thanks for noticing it! I've updated the spigot page.
Sadly I can't make it easily searchable that "4.9.1 is still valid for version 1.7+ -> 1.20.4"... I just added it as a separate topic on the spigot page.
Spigot Page
1.17 and under support was stripped as a part of this commit. The tested minecraft versions and list of supported versions in the descriptions should be updated to reflect the change.