Strong spin-orbit coupling (SOC) has often lead to exotic properties in otherwise banal pool of 'paramagnetic' heavy ion oxides. In this context d4 Ir systems are exciting because for a 5d4 system a J=0 total angular momentum ground state should be realised in a jj coupling scheme, which has not been realized till today. This is due to the presence of a complex interplay and a subtle balance between interelectronic repulsion, correlation, crystal field and SOC, which makes the J=0 state a fragile one. In our last muSR beamtime at ISIS we could successfully probe the magnetic ground state of Ba2YIrO6 down to 60 mK which should help to close the actual controversy on this compound. However, situations with other systems Ba3MgIr2O9, Sr2LuIrO6 and Sr3LiIrO6 are still not understood and require detailed muSR studies down to milli-Kelvin temperatures