* Open `app/docker-compose.yml` and locate `riot` (the Element Web service) and `synapse` (the Matrix Synapse server). There are two things you need to do for each service:
* Set the `VERSION` argument to the target service version (e.g. `1.26.0` for Synapse). This argument is then used to template the Dockerfile.
The `VERSION` value should match a github release, the link to the corresponding release page is put as a comment next to the variable in the compose file;
* Tag the image with a new incremented version tag. For example: `superboum/amd64_riotweb:v17` will become `superboum/amd64_riotweb:v18`.
We use the docker hub to store our images. So, if you are not `superboum` you must change the name with your own handle, eg. `john/amd64_riotweb:v18`. This requires that you registered an account (named `john`) on https://hub.docker.com.
So, from now we expect you have:
* changed the `VERSION` value and `image` name/tag of `riot`
* changed the `VERSION` value and `image` name/tag of `synapse`
From the `/app` folder, you can now simply build and push the new images:
I built a test stack with docker-compose in `app/<service>/integration` that should help you out (for now, test suites are only written for plume and jitsi).