Installing version 3.2.20.10 is a manual process as Oracle does not provide an automated installer for this build. Oracle Forumshttps://forums.oracle.com Where can I get an older version? - Oracle Forums
If you encounter connection issues with a very old database (e.g., Oracle 8i or 9i), replace the ojdbc6.jar in sqldeveloper\jdbc\lib with an appropriate version from Oracle’s JDBC download archive. Oracle Sql Developer 3.2.20.10 Download