BlueSpice is currently compatible with Elasticsearch 6.x as of version 6.3.1.
The latest version can be found at this list. This results in the following direct download link: https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-<version number>.zip. For example, https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.3.1.zip.
Follow the download instructions of your browser.
Unpack the contents of the ZIP archive (2) just downloaded into the folder "C:\bluespice\bin\elasticsearch-6.3.1" (1):
Installing the plugin ingest-attachment
Change to the directory "C:\bluespice\bin\elasticsearch-6.3.1\bin" (1) and right-click on a free area of the Explorer window with the Shift key pressed. Then click "Open Command Prompt Here" (2):
Execute the command "elasticsearch-plugin.bat install ingest-attachment" (1) and after downloading the plugin, confirm the installation request with "y" (2):
Installing the Elasticsearch service
Next, run the elasticsearch-service.bat install command and wait for the process to complete:
Configuring and starting the Elasticsearch service
Press the key combination Windows+R.
In the following dialog box, enter "services.msc" (1) und confirm with "OK" (2):
Search for the service "Elasticsearch 6.3.1" and open it with a double-click:
Select the startup type "Automatic" (1) and start the service (2). After the service is started, close the window with "OK" (3):
If you have completed all steps successfully, you can delete the previously downloaded file "elasticsearch-6.3.1.zip" from your hard disk and continue to the next step "Git".