I have some routers running 12.4(3) a different feature set than yours. I checked my routers and both ip classless and ip subnet-zero do still appear in the running config. So I do not think that there is a general change release wide. Perhaps it is something in your specific version and feature set.
FCS makes reference to the fact that most commands do not show up in the running-config if they are set to their default value. Both ip classless and ip subnet-zero have been exceptions to this, because in their history the default has changed (both were originally not enabled by default and now both are enabled by default). It is possible that in your version of code that someone decided to hide them to conform to the usual do not show commands when set to default values.
We are pleased to announce availability of Beta software for 16.6.3.
16.6.3 will be the second rebuild on the 16.6 release train targeted
towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are
looking for early feedback from customers befor...
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