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.
Duty to provide child support is usually discontinued at age of majority, but the court may order a parent to pay support beyond 18. Support may be extended until until age 19 1/2 while completing high school, or beyond age 19 1/2 by agreement of all parties involved.