Oracle Instant Client libraries installation
Download Oracle Instant Client libraries (URL may change, already happened few times). Be sure you download correct (x64 or x32) architecture. And correct version.
Last time I used Client 22.214.171.124.0 with Oracle 12c and PHP 8.1.
Before that Instant Client 126.96.36.199.0 with Oracle 12c and compiled with PHP 8.0, 7.4 and 7.3 fine.
Before that Instant Client 10.1.0.5.0 with Oracle 10g, 11g and 12c and PHP 5.6, 7.1, 7.2, 7.3 and 7.4.
Never hit any problem with such setups but my queries are quite simple. One should be fine with the newest version. It should be backward compatible (fingers crossed).