SoapUI-5.5.0: ExceptionInInitializerError during configuration of log4j from soapui-log4j.xml

Hello community,

I'm having issues while upgrading to SoapUI 5.5.0: I'm getting an ExceptionInInitializerError exception while configuring log4j from soapui-log4j.xml. So far the answer i've found are related to the issue reported on https://community.smartbear.com/t5/SoapUI-Open-Source/SoapUI-5-4-0-ExceptionInInitializerError-during-new-settings/m-p/156913#M26056 but now i'm not getting that error anymore (I tried the propsed soution and replaced the soapui-settings.xml and now i'm ok with that). Can somebody please help me on this? 

FYI: I'm running SoapUI 5.2.0 and it's working fine.