We fork Prometheus from OpenShift (https://github.com/openshift/prometheus) and add our own content on top. This repo forks Prometheus based on OpenShift version rather than one based on any specific release of Prometheus. There are tags that are similarly versioned, but again, these map to OpenShift versions rather than Prometheus versions.

The version of Prometheus that we are currently using in maistra-2.1 is based on the 4.3 release of OpenShift, which was last updated in December 2019.

Istio 1.8 & 1.9 are based on Prometheus 2.21 while 1.10 is based on 2.24 – https://github.com/istio/istio/blob/release-1.9/samples/addons/prometheus.yaml#L427