I installed csound-3.50 on Linux and tried to use it via MIDI in realtime.
The first problem was that envlpxr was not there any more (already reported).
I have fixed this now (very simple):

In the file entry.c, insert the line
void    evrset(void*), knvlpxr(void*), envlpxr(void*);

after the line
void    evxset(void*), knvlpx(void*), envlpx(void*);

Further, insert the line:
{ "envlpxr",S(ENVLPR),  7,      "s", "xiiiiiooo", evrset,knvlpxr,envlpxr},

after the line
{ "envlpx", S(ENVLPX),  7,      "s", "xiiiiiio", evxset, knvlpx, envlpx},

and recompile.

Next problem: I previously used the Unofficial Linux Csound 
Version  v3.49.4.0a. There, the option -M/dev/midi00 worked well. In 3.50,
nothing is received from the MIDI port, and I have to 'cheat' like that:
cat /dev/midi00 | csound -Mstdin etc
which works.

Third problem (and worst): The audio quality: While in the 3.49.4 version,
the sound was clean and HiFi, in the 3.50 version I get annoying clicks
at every note-on and note-off (worse at note-off's) with the same
orchestra I used before



Thomas