@slowsmile: I experienced the same tkinter layout problems on my Arch Linux machine as
DiapDealer.
As for bk.epub_version(), it's a relatively recent addition. You might want to add a fallback for older versions. For example:
Code:
# get epub version number
if bk.launcher_version() >= 20160102:
epubversion = bk.epub_version()
else:
epubversion = BeautifulSoup(bk.get_opf(), 'lxml').find('package')['version']
Of course you could also simply state that your plugin requires Sigil 0.9.3 or higher.