Can I use this feature in a given web browser in a given version?

If you are developing for the web you certainly were confronted by the question if a given web feature (webrtc, URLSearchParams, …) is supported by browsers and which versions of them. To answer this question you can use the website https://caniuse.com.

Check if port on remote server is open without using telnet

If you want to check if a given port is open on a given remote server, you can use telnet. More and more telnet disappears on server. So the question arises: What can we use instead of telnet? Short answer: netcat. For example:

nc -zv 192.168.1.15 22

Which checks if the port 22 (SSH) is open on the server 192.168.1.115