Hi,
My question is with regard to the backward compatability of the plugins i.e. can you run your V1.9/ V2.3 and install a latest and greates plug in.
Thank you
1.9? No chance.
2.3? Probably it will work.
That is, each new Moodle version will not gratuitously break plug-ins, but improvements in the core Moodle platform may require some changes to plugins for them to go on working. The plugins database (https://moodle.org/plugins/ ) does a good job of documenting what works with what.