Rambam codified them in Mishnah. He codifies in other places aside from Mishnah Torah. Codify means to “Arrange (laws or rules) into a systematic code”.
Where do we say prayers to angels? Examples would help.
We sing Shalom Aleichem. However, all we are doing is blessing the angels, asking for blessings from the angels and giving them farewell. Is getting a blessing from a great person in violation of the 5th ikkar? No. Especially since the blessing is really a prayer to G-d for that person, openly stated or implied. Why is it different with angels? We are asking them to bless us, no prayers to them.
Machnesai rachamim. (Some do not say it) Those who do, once again, are not praying to angels. The Rambam does not say you can not SPEAK to them or REQUEST something. He says not to to PRAY. We ask them to bring our prayers in front of God since Hashem created a process in how prayers ascend to him (yaleh, vyavo, vyageya…). If anything it perhaps AFFIRMS the Rambam’s position.
Do you have any other cases?