1. Skype itself is a closed-source, proprietary computer program, and you have no way to know what it is actually doing at any point in time.
2. All communications, including audio, video, text, and file sharing, are passed through Skype's (Microsoft's?) servers, and is readable by them.
3. If it is readable by Skype (Microsoft?), then it is readable by any government agency with access to their servers, whether by court order or voluntary participation.
"Is Skype currently safe?" Safe from what? The NSA recording your conversations? Microsoft selling marketing information? Your competitors doing a bit of corporate espionage? Accidentally recording calls to a YouTube channel?
That is, what is your threat model?
Some of my clients, at a big pharmaceutical company, use Skype for Business (nee Lync), so I know some businesses find the risks to be acceptable.
Well one way to test is to put honey links into an IM session and see which ones are pinged. Invariably they will be pinged from a co-lo situated in a remote U.S data center.
2. All communications, including audio, video, text, and file sharing, are passed through Skype's (Microsoft's?) servers, and is readable by them.
3. If it is readable by Skype (Microsoft?), then it is readable by any government agency with access to their servers, whether by court order or voluntary participation.
It's your call.