https://www.oschina.net/news/115035/php-7-4-5-released

opkg update

opkg install php7.4

opkg install php7.4-fpm

opkg install php7.4-base

opkg install php7.4-mod-bz2

opkg install php7.4-mod-curl

opkg install php7.4-mod-iconv

opkg install php7.4-mod-mbstring

opkg install php7.4-mod-zip

opkg install php7.4-mod-gd

service php74-fpm restart