Complex sentence: Within several months from this date, in order to continue using Skype services, Skype users had to update to Skype applications released in 2014, and users were not able to log in to older Skype versions (clients).
Split into simpler sentences: Within several months from this date, in order to continue using Skype services, Skype users will have to update to Skype applications released in 2014. Users will not be able to log in to older Skype versions (clients).