After looking more into it: seems that constellation configuration has been changed in Pega 8.8. Now new DSS was introduced: ConstellationPegaStaticURL and docker image for ConstellationSvcURL DSS has been changed as well.
But links seems to be broken and docker image for appstatic cannot be pulled:
$ docker pull pega-docker.downloads.pega.com/constellation-appstatic-service/docker-image:0.0.3-20220112124450309
Error response from daemon: manifest for pega-docker.downloads.pega.com/constellation-appstatic-service/docker-image:0.0.3-20220112124450309 not found: manifest unknown: The named manifest is not known to the registry.