We are interested in using YugabyteDB (https://www.yugabyte.com/yugabytedb/) as our database and we would like to know if Cognos 11.2.4 fp2 supports it.

We could not find any information about this in the supported db list in the URL: https://www.ibm.com/software/reports/compatibility/clarity-reports/report/html/prereqsForProduct?deliverableId=2FBD998D785647B2AB4CBDF806ECB59A#sw-5

Please let us know if this is a compatible option...

If YugaByte database can support JDBC driver to connect, will Cognos be able to connect to Yugabyte via JDBC driver? 

There are products in the market, such as Yugabyte which will state their compatibility relative to PostreSQL.

https://docs.yugabyte.com/preview/explore/ysql-language-features/postgresql-compatibility/

In turn, applications would have to connect using the PostgreSQL JDBC driver.

This does not mean that Cognos Analytics is claiming to have been tested with said product and where necessary made changes specific to that product etc.

Should you encounter an issue and attempt to contact Cognos support, you will be asked to duplicate the issue using a version of PostgreSQL which Cognos Analytics is integrated and supports etc.