for back-end please use fep_save_announcement.
Next update will be a major update of this plugin. Most of the code is changed in this version. Please read https://wordpress.org/support/topic/need-help-for-testing-new-beta-version-10-0-1beta1/ to make your changes compatible with future release.
See https://github.com/shamim2883/front-end-pm/tree/1001beta1 for code