Words in Gforth manual undefined

I discovered that some words documented in the Gforth manual, like MAX-U
(environment wordset) and u/ (gforth-1.0 wordset), are undefined in my
installations of Gforth 0.7.3.

Is there something messed up with my installations, or is there
something else (Forth command, installation, Gforth upgrade) to make
such words/wordsets available in my Gforth environment?

--
David Meyer
Takarazuka, Japan
papa@sdf.org