Версия языка PHP 5.6 доступна на всех тарифах хостинга cPanel hosting.
Как изменить версию PHP написано в статье Выбор версии PHP.

PHP 5.6 (количество модулей 152): apcu, apm, ares, bcmath, big_int, bitset, brotli, bz2, bz2_filter, calendar, core, ctype, curl, date, dba, dbx, dom, doublemetaphone, eio, enchant, ereg, exif, ffmpeg, fileinfo, filter, ftp, gd, gender, geoip, geos, gettext, gmagick, gmp, gnupg, grpc, haru, hash, htscanner, http, iconv, igbinary, imagick, imap, inotify, interbase, intl, ioncube_loader, ioncube_loader_4, jsmin, json, ldap, libevent, libsodium, libxml, luasandbox, lzf, mailparse, mbstring, mcrypt, memcache, memcached, mhash, mongo, mongodb, msgpack, mssql, mysql, mysqli, mysqlnd, ncurses, nd_mysql, nd_mysqli, nd_pdo_mysql, oauth, oci8, odbc, opcache, openssl, pcntl, pcre, pdf, pdo, pdo_dblib, pdo_firebird, pdo_mysql, pdo_oci, pdo_odbc, pdo_pgsql, pdo_sqlite, pgsql, phalcon, phalcon3, phar, posix, propro, pspell, quickhash, radius, raphf, rar, readline, recode, redis, reflection, rsync, session, shmop, simplexml, snmp, soap, sockets, solr, sourceguardian, spl, spl_types, sqlite3, ssh2, standard, stats, stem, stomp, suhosin, sybase_ct, sysvmsg, sysvsem, sysvshm, tideways, tidy, timezonedb, tokenizer, trader, translit, uploadprogress, uri_template, uuid, wddx, weakref, xcache_3, xdebug, xhprof, xml, xmlreader, xmlrpc, xmlwriter, xrange, xsl, yaml, yaz, zend_guard_loader, zip, zlib, zmq