The documentation seems to indicate that the right maven repository to use is:

  <repository>
     <id>osgeo</id>
     <name>Open Source Geospatial Foundation Repository</name>
     <url>http://download.osgeo.org/webdav/geotools/</url>
  </repository>

However it seems that the latest version on this repository was last updated in 2014. https://mvnrepository.com/artifact/org.geotools.jdbc/gt-jdbc-postgis?repo=osgeo

On the other hand the Boundless one seems to be carrying a much more updated version than the other repositories. This one was last updated in September 2018: https://mvnrepository.com/artifact/org.geotools.jdbc/gt-jdbc-postgis/20.0

However, the documentation states that the Boundless repository is for snapshots.

Which is the proper version to use?

The documentation seems to indicate that the right maven repository to use is:

  <repository>
     <id>osgeo</id>
     <name>Open Source Geospatial Foundation Repository</name>
     <url>http://download.osgeo.org/webdav/geotools/</url>
  </repository>

However, it seems that the latest version on this repository was last updated in 2014. https://mvnrepository.com/artifact/org.geotools.jdbc/gt-jdbc-postgis?repo=osgeo

On the other hand, the Boundless one seems to be carrying a much more updated version than the other repositories. This one was last updated in September 2018: https://mvnrepository.com/artifact/org.geotools.jdbc/gt-jdbc-postgis/20.0

However, the documentation states that the Boundless repository is for snapshots.

Which is the proper version to use?