Both RFC 6020 7.1.9 and RFC 7950 7.1.9 state that the revision history statements "should" be in reverse chronological order. In tailf-netconf-ncs.yang, I see the following order with the two latest entries out of order:
revision 2016-06-14
revision 2016-11-24
revision 2016-05-26
revision 2014-11-19
revision 2014-06-30
revision 2014-05-20
revision 2013-06-18
I needed to modify my copy to make a tool I am using to stop complaining.
