From Fedora Project Wiki
httpd was updated from 2.2.17 to 2.2.19. This version is principally a security and bugfix release. This release also corrects a versioning incompatibility in 2.2.18; users are advised that 2.2.19 now restores compatibility with modules compiled against earlier versions of 2.2 (other than 2.2.18 which is considered abandoned).
- Revert ABI breakage in 2.2.18 caused by the function signature change of ap_unescape_url_keep2f(). This release restores the signature from 2.2.17 and prior, and introduces ap_unescape_url_keep2f_ex().