This plugin only lists very outdated Atlassian product versions as compatible. The Marketplace page states that Confluence Server 5.0 - 5.8.18 are compatible.
Could the plugin be updated to support the newer Confluence (and JIRA) release series such as 5.9.x, 5.10.x, and 6.0.x (latest as of now is 6.0.3)?
If that isn't possible, alternatively would it be possible to release the plugin as open source to allow the community to update it over time and still make releases available via the Marketplace? Even having the source code would be helpful as individual companies/groups could update, compile, and install it in newer Confluence releases.