I have never used octal numbers in my code nor come across any code that used it. I bet you have. According to the standard, numeric literals which start with zero are octal. This includes, trivially, 0. Every time you have used or seen a literal zero, this has been octal. Strange but true.
If you are making child support payments in Texas, the law generally requires you to do so until your child turns 18, which is the age that marks adulthood in the state, or when he graduates from high school -- whichever comes later.
A support obligation may continue for a child who is 18 and still attending high school. When a child is emancipated, or over 18 years of age and no longer attending high school, one of the parents may file a Petition for Modification of an Existing Support Order to request that the child support order be stopped.