PHP includes a large number of extension in its standard distribution. Those are available in the php-src repository and the source download, the other extensions are available in PECL.

php standard distribution evolution

In PHP 5.0, there was 84 standard extensions, and there will be 70 in PHP 7.4. The number of extension has been dropping regularly. Extensions are moved to PECL when they are not ported to the new version, or are not maintained anymore.

Number of extension in PHP standard distribution, from 5.0 to 8.0

In PHP 7.4. interbase (ibase) and wddx are moved to PECL, while ffi (Foreign Function Interface) is added to the distribution. That’s a net reduction of 1 extension.

Here is the detailled evolution of all extensions, since PHP 5.0.

8.0 7.4 7.3 7.2 7.1 7.0 5.6 5.5 5.4 5.3 5.2 5.1 5.0
bcmath
bz2
calendar
com_dotnet
cpdf
ctype
curl
date
dba
dbase
dbx
dio
dom
enchant
ereg
exif
fam
fbsql
fdf
ffi
fileinfo
filepro
filter
ftp
gd
gettext
gmp
hash
hwapi
iconv
imap
informix
ingres_ii
interbase
intl
json
ldap
libxml
mbstring
mcrypt
mcve
mhash
mime_magic
ming
mnogosearch
msession
msql
mssql
mysql
mysqli
mysqlnd
ncurses
oci8
odbc
opcache
openssl
oracle
ovrimos
pcntl
pcre
pdo
pdo_dblib
pdo_firebird
pdo_mysql
pdo_oci
pdo_odbc
pdo_pgsql
pdo_sqlite
pfpro
pgsql
phar
posix
pspell
readline
recode
reflection
session
shmop
simplexml
snmp
soap
sockets
sodium
spl
sqlite
sqlite3
sybase
sybase_ct
sysvmsg
sysvsem
sysvshm
tidy
tokenizer
w32api
wddx
xml
xmlreader
xmlrpc
xmlwriter
xsl
yp
zip
zlib