What is the legal ruling on someone who commits an abomination out of ignorance?

One who commits an indecency out of ignorance is excused if someone like them could be ignorant of it, such as less well-known prohibitions. The prescribed punishment (hadd) is waived for them because these punishments are part of the خطاب التكليف (address of responsibility) which is directed at the legally competent person who is aware of the prohibition. However, if it is something known by necessity in the religion, like fornication (zina) or drinking alcohol, then they are not excused unless they are a recent convert to Islam. As for the خطاب الوضع (address of placement), it applies to everyone, such as liability for damages. Repentance is obligatory for one who commits an indecency out of ignorance.