I have uploaded ReleaseDog v10.3.6 into JIRA v5.2.0. Manual upload was necessary because, at time of writing, ReleaseDog does not yet officially support this version of JIRA.
ReleaseDog seems to work fine with JIRA v5.2.0, but the Calendar Gadget displays with a lot of wasted space (see attached screenshot) for all but the first of the 5 available dashboard layouts. ie, it looks OK in single column layout.
I suspect that the cause might be the same thing that is leading to issues https://bitbucket.org/abhijitjadeja/releasedog/issue/15 and https://bitbucket.org/abhijitjadeja/releasedog/issue/26... but I'll let the developer be the judge of that.
I am not very good with XML but I do notice that the content element in the XML for both the Calendar and the View Gadgets contains no reference at all to "height".