more changes to readme

Author: tdudgeon

README.md

@@ -18,7 +18,7 @@ For each RDKit version (image tag) we build a number of images:
 * [informaticsmatters/rdkit-python3-debian](https://hub.docker.com/r/informaticsmatters/rdkit-python3-debian/) - a Debian based distribution designed for running RDKit from Python 3. Thes images start from the `Release_2019_03` release.
 * [informaticsmatters/rdkit-java-debian](https://hub.docker.com/r/informaticsmatters/rdkit-java-debian/) - a Debian based distribution designed for running RDKit from Java.
 * [informaticsmatters/rdkit-tomcat-debian](https://hub.docker.com/r/informaticsmatters/rdkit-tomcat-debian/) -  a Debian based distribution designed for running a servlet in Apache Tomcat that uses the RDKit Java bindings. You need to provide the war file with the web application.
-* [informaticsmatters/rdkit-cartridge-debian](https://hub.docker.com/r/informaticsmatters/rdkit-cartridge-debian/) - a Debian based distribution with PostgreSQL and the RDKit cartridge. 
+* [informaticsmatters/rdkit-cartridge-debian](https://hub.docker.com/r/informaticsmatters/rdkit-cartridge-debian/) - a Debian based distribution with PostgreSQL and the RDKit cartridge. Note that we were unable to build cartridge images for the 2021_09 and 2022_03 based releases.
 * [informaticsmatters/rdkit-build-centos](https://hub.docker.com/r/informaticsmatters/rdkit-build-centos/) - Kitchen sink build image equivalent to `informaticsmatters/rdkit-build-debian`.
 * [informaticsmatters/rdkit-python3-centos](https://hub.docker.com/r/informaticsmatters/rdkit-python3-centos/) - a Centos based distribution designed for running RDKit from Python 3. Thes images start from the `Release_2019_09` release.
 * [informaticsmatters/rdkit-java-centos](https://hub.docker.com/r/informaticsmatters/rdkit-java-centos/) - a Centos based distribution designed for running RDKit from Java.