Need WEP encryption mode!

I have a Metal 2.. I need WEP encryption mode. Then I didn’t find him. What’s the solution?
HELP!

Check out the manual: https://wiki.mikrotik.com/wiki/Manual:Interface/Wireless#WEP_properties

However, since nowadays WEP-protected networks are virtually no different than open networks, I’m kinda curious what do you need it for?

Thank you very much. Because there are many clients that are very old products. Only the WEP encryption function, and can not be arbitrarily modified