Update system not working as expected

software update gives the following error:

Unable to check update due to a system error: Error running a command. cmd = [’/usr/bin/yum’, ‘changelog’, ‘2016-Feb-26’, ‘rockstor’]. rc = 1. stdout = [‘Loaded plugins: changelog, fastestmirror’, ‘’]. stderr = [‘Traceback (most recent call last):’, ’ File “/usr/bin/yum”, line 29, in ‘, ’ yummain.user_main(sys.argv[1:], exit_code=True)’, ’ File “/usr/share/yum-cli/yummain.py”, line 365, in user_main’, ’ errcode = main(args)’, ’ File “/usr/share/yum-cli/yummain.py”, line 174, in main’, ’ result, resultmsgs = base.doCommands()’, ’ File “/usr/share/yum-cli/cli.py”, line 573, in doCommands’, ’ return self.yum_cli_commands[self.basecmd].doCommand(self, self.basecmd, self.extcmds)’, ’ File “/usr/lib/yum-plugins/changelog.py”, line 215, in doCommand’, " if self._since_dto == dateutil_parser.parse(‘garbage’, fuzzy=True):", ’ File “/usr/lib/python2.7/site-packages/dateutil/parser.py”, line 1161, in parse’, ’ return DEFAULTPARSER.parse(timestr, **kwargs)’, ’ File “/usr/lib/python2.7/site-packages/dateutil/parser.py”, line 555, in parse’, ’ raise ValueError(“String does not contain a date.”)’, ‘ValueError: String does not contain a date.’, ‘’]

i updated the kernel manually (now running 4.5.0-1) and i tried downgrading python.

no luck.