Good afternoon,

The -egen, xtile- command/function from the egenmore package by Nick Cox is exhibiting some concerning behaviour: it works under Stata 11,12,13, but it generates the following error message under Stata 15:

Code:
. webuse nlswork, clear
(National Longitudinal Survey.  Young Women 14-26 years of age in 1968)

. 
. keep idcode year ln_wage hours

. egen xtiles = xtile(ln_wage), by(idcode)
too many values
r(134);

.
I believe the problem is a point in the code of - _gxtile- where an outdated command which fails under Stata 15 (but works under Stata 11,12,13) is used:

Code:
. levels idcode
too many values
r(134);

. levelsof idcode
******** output omitted, but it works
My questions is, Is this not supposed to never happen? Are the commands / functions in Stata not supposed to be backward compatible?