25th May is the day when new GDPR rules will come into action and can be the reason Microsoft is pulling out wires from old Skype versions. Although it is being seen that due to this new rule Microsoft and other companies are continuing to disconnect their old applications, in this case, you will have to install the new version of such old applications to get better security and performance.
Microsoft is thinking of continuing to discontinue the old version. If you are using the old Skype version, then you will get a notification from Microsoft which will be as follows.
We noticed you are using a version of Skype for Windows 10 that will no longer work after May 25, 2018. Older conversation history may be impacted during the upgrade. If you need help backing up your chat contact us. Not able to upgrade? Tell us more.
Microsoft has been sending emails to people who are still using the old version of Skype to upgrade to the new version or risk losing the conversations. It can also be assumed that this comes after all the major companies revamped their Data Protection guidelines in consequence of new GDPR rules for the European Union.
Note: Make sure to take a backup of chats, It’s something that you should do before re-installing the new Skype version. Though if you have some important chats, take a screenshot of those as a user had a problem restoring old chats (source).
To install latest Skype.
This link will lead you to Skype App in Microsoft store.