In 2019 the asciidoctorj implementation switched to 2.x and changed the minimum Java version to 8.
This change fixed many issues with extensions, but also brought some incompatible changes in the extension api with the 1.5.x. version of asciidoctorj (currently used by asciidoclet).
To be able to use the new generation of asciidoctorj extensions in asciidoclet the version of asciidoctorj needs to be upgraded to 2.x (e.g. current stable version 2.4.2).
In 2019 the asciidoctorj implementation switched to 2.x and changed the minimum Java version to 8. This change fixed many issues with extensions, but also brought some incompatible changes in the extension api with the 1.5.x. version of asciidoctorj (currently used by asciidoclet).
To be able to use the new generation of asciidoctorj extensions in asciidoclet the version of asciidoctorj needs to be upgraded to 2.x (e.g. current stable version 2.4.2).