GoldenGate 188.8.131.52.2 (or December release) was uploaded to edelivery.oracle.com. If you use GoldenGate Microservice Architecture then it is essential to download new version because it has some new features and bugs fixed.
I couldn’t find instructions how to upgrade GG 12.3 Initial Release to GG 184.108.40.206.2 December Release. So I chose the following method:
1) Install GG 220.127.116.11.2 to new directory (for example to directory /u01/app/oracle/product/gg/12.3_ma/db122_december — this is GG for DB 12c)
2) Move existing directory (I moved /u01/app/oracle/product/gg/12.3_ma/db122 —> /u01/app/oracle/product/gg/12.3_ma/db122_initial)
3) Create link for old directory which will point to last installed version (link /u01/app/oracle/product/gg/12.3_ma/db122 ——> /u01/app/oracle/product/gg/12.3_ma/db122_december)
Restart everything. You should see new version in Service Manager