tex() uses obsolete "over"



when using MikTeX to latex a tex file, and when I am using the amsmath 
package, I get the warning:

Package amsmath /b/c12/cWarning:/b/c0/c Foreign command \over;
(amsmath)                \frac or \genfrac should be used instead

Maxima tex() function, applied to, for example:

                         c + 2 b + 4 a
(%o4)                 -------------
                             4 e + 8 d

(%i5) tex(%);

$${{c+2\,b+4\,a}\over{4\,e+8\,d}}$$

(%o5)          false

The tex() example in the Maxima Manual shows that "over" is used rather than 
"frac".

Ted Woollett
win xp 5.12