Hello and thanks for your report!
The error states that the plugin has been compiled to be ran with java 1.7 or higher. Its a packaging problem of the plugin which is downloaded from igniterealtime.org, report the problem there.
Note however that as our "Bugs and Issues" page  explains, we expect
reports to be submitted in the issue tracker once they have been
and confirmed as such on our dev mailing list . This is really
important to us and we've tried to make it clear throughout the site. You
may also like to check the following page  for the rationale behind
For all these reason we may be marking this issue as Invalid. In all
cases, please report it on firstname.lastname@example.org so that we can have a proper
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