Skype's popularity has severely diminished over the years, but if you somehow still know 50 people using the service, Microsoft has some good news for you. Starting with version 18.104.22.168, currently only available for Skype Insiders, you'll be able to engage in group calls with up to 50 people, up from the previous limit of 25.
To go along with this expansion, Microsoft is also making call notifications a little less annoying, so you won't ring all 50 group members whenever you start a call. Instead, a regular notification will be sent, providing a less intrusive way for people to join the call, though if you really want to, you can still ring individual members if their presence is especially important. This feature is also being brought to group video calls, regardless of group size.
Microsoft has continually been improving Skype v8, and earlier this week another update improved the mobile apps for Insiders as well. A recent update added a picture-in-picture mode for YouTube videos shared within Skype, so you don't have to switch back and forth between the conversation and the video.
If you're interested in trying out the latest updates to Skype, you can join the Skype Insider Program. Or you can wait for the feature to make its way to the general public, which shouldn't take too long.