> The Dockerfiles used to build the images that the Polar app needs to spin up nodes quickly across multiple operating systems.
_Warning: These images are not hardened and shouldn't be used to store real bitcoin. These images are intended solely to be used in simnet/regtest environments_
These docker images can be updated in-between Polar releases. This allows developers to use the latest Bitcoin & Lightning versions shortly after they are released, without needing to download and install a new version of Polar.
To make new docker image versions available:
1. Build the new docker image using the commands above
1. Push the image to Docker Hub
1. Update the [`/docker/nodes.json`](https://github.com/jamaljsr/polar/blob/master/docker/nodes.json) file
- add the new version to the `versions` array of the associated implementation
- update the `latest` property of the implementation if necessary
- increment the root-level `version` number by `1`
Once the updated `nodes.json` file is committed to master, the new images can be used in Polar by following these steps:
1. Create a Network or view an existing Network
1. In the Network Designer sidebar, click on the **Show All Versions** toggle
1. At the bottom of the node list, click on the **Check for new Node Versions** link
1. A dialog will open displaying the new versions available
1. Click the **Add New Versions** button to begin using them