First, you want to first make sure that you stop your current SDK instance container from running on Docker. 

Once you have done this, pull the images of the version you want to update your SDK instance to from Docker, using the following command:

Pull the images
docker pull itext/dito-sdk:{upgraded version}

Start the new SDK Instance in the Same Directories and Port Number as Your Previous Instance 

If you would like to store the upgraded SDK instance in the same directory and port number as your current one, please run the following command:

Pull the images
docker run -it --name updated-dito-sdk-instance
         -v {path to config directory as previous SDK instance}:/etc/opt/dito/shared
         -v {path to work directory as previous SDK instance}:/var/opt/dito
         -p {same port as last SDK instance}:8080
         itext/dito-sdk:{upgraded version}