Fail to compile with ejabberd 17.04

Hi,

I got into the folllowing warning during compilation:

Recompile: src/mod_offline_post
src/mod_offline_post.erl:31: Warning: undefined callback function depends/2 (behaviour 'gen_mod')
src/mod_offline_post.erl:31: Warning: undefined callback function mod_opt_type/1 (behaviour 'gen_mod')

Any idea on how to fix it ? Thanks