ojdbc8.jar not picking up in SOAPUI 5.3.0

Hi,

We are using SOAPUI open source v5.3.0 for API testing. Up until now we were using ojdbc6 however, we recently switched to ojdbc8. I manually added the jar file to /Contents/java/app/lib folder as well as jre/lib/ext folder. However, SOAPUI does not seem to be picking up the jar to execute the JDBC steps.

java.sql.SQLException: No suitable driver found for jdbc : oracle:thin:@(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(PORT=XXXX)(HOST=XXXX)))(CONNECT_DATA=(SERVICE_NAME=XXXX))) 

At this point we are blocked with our tests due to this. Please advice.