The modern libsodium cryptography library has now become a core extension in PHP (as ext/sodium).
The utf8_encode() and utf8_decode() functions have now been moved to the standard extension as string functions.
sql.safe_mode ini setting
The sql.safe_mode ini setting has now been removed.
realpath_cache_size ini setting changed
The default value of the realpath_cache_size ini
setting has changed from 16 kilobytes to 4 megabytes.