Our 2003 source release already included Unicode support with UTF-8 and transcoding to multiple codepages; support for the xterm-style 256 colour modes, and TLS connections. We are the first nown mud (to us) to support all three of these.
Internal commit history dates our TLS (then known as SSL) support to May 2003. It did not make the public source release of that year, but external evidence on the wayback machine demonstrates it was documented by December 2003.
We continue to support TLS, but now have removed direct support from the codebase and instead use stunnel to provide a wrapper.
This can be observed in our 2003 source release.
Internal commit history shows that we added this in 2002.
Internal commit history shows a player mode to select Unicode output was first added in early 2001.
By the time of the source release in 2003 this had grown to support for several then-common codepages (latin1, cp850, cp437, koi8r, macroman, windows-1252), and decoding and encoding them for players, along with a wcwidth() implementation. current versions have many more encodings, a large table of fallback characters for Unicode characters; and have moved to UTF-8 as the source and execution character set.
this dates to 2002 - and analagous to MXP <frame>, but terminals. I don't know if I'd actually do this as a telnet extension. Crystal is probably the only client to support this.
from 2025. a mechanism for command responses to be tagged with the an opaque ID representing the command, so the client can know exactly what responses correspond to exactly what commands. this was devised for making our automated tests more reliable.
MusicMUD/Cryosphere can use OSC 639 to tag language codes
for example,
␛]639;fr␛\ means French,
␛]639;en-GB␛\ means British English,
␛]639;␛\ means reset to default language (undifferentiated/user
specific).
It will only do this if it detects Chrysalis web client, or if OSC639_LANGUAGE is set to 1 via NEW_ENV
These codes could be full IETF language tags
The OSC639 language property is supposed to survive a reset of general ansi state such
as by ESC[0m