Let me Google that for you.
supporting DICT, FILE, FTP, FTPS, GOPHER, GOPHERS, HTTP, HTTPS, IMAP, IMAPS, LDAP, LDAPS, MQTT, MQTTS, POP3, POP3S, RTSP, SCP, SFTP, SMB, SMBS, SMTP, SMTPS, TELNET, TFTP, WS and WSS. libcurl supports SSL certificates, HTTP POST, HTTP PUT, FTP uploading, HTTP form based upload, proxies, HTTP/2, HTTP/3, cookies, user+password authentication (Basic, Digest, NTLM, Negotiate, Kerberos), file transfer resume, http proxy tunneling and more!
libcurl is highly portable, it builds and works identically on numerous platforms, including Solaris, NetBSD, FreeBSD, OpenBSD, Darwin, HPUX, IRIX, AIX, Tru64, Linux, UnixWare, HURD, Windows, Amiga, OS/2, BeOs, macOS, Ultrix, QNX, OpenVMS, RISC OS, Novell NetWare, DOS and more...
Maybe there is place for a minicurl which removes BeOS and Novell NetWare...
https://curl.se/docs/releases.html
If you dig into them you'll see there's lots of features that aren't adding new protocols. But incidentally they added a new protocol in March (mqtt). You'll also see that the list of bug fixes is prolific.
Then there are also HTTP/2 and HTTP/3.
That's just HTTP, curl supports 27 other protocols.
It's not like the standard changed since curl was created