Thanks for that info. Something I am looking into. Before I upgrade, I might want to also add MediaLab (which I have never used) to the DirectRT upgrade. The reason being that there is a particular experiment I am trying to code, which has two distinct blocks of trials and I need to randomize trials separately in the two blocks. From what I understand, DirectRT cannot do this. But, I read in another thread that if I use MediaLab, I could link and present sequentially two separate DirectRT files (each coding for the different blocks). Is this correct?