Select the most up-to-date Eclipse Scout release anytime you start a new project. In case you still need an older version for historical research, you can find it here.
Major Scout versions are released twice a year. The first release of a year gets updates until the second release is published. After that, the first release becomes unsupported. The second release gets LTS status (long-term support) which means critical bugs will be fixed for about 2 years.
The first number (major) of the version represents the year. The second number (minor) represents the release within that year. The third number (micro) is increased on every bug-fix update.