There are definite advantages to using Tanner v15.23 for me as I like to drag cells across technology files to quickly get known cells into another technology. After doing so you are then prompted to choose the layers you want your features to go to in the new technology file. This ability was eliminated when Tanner bridged into open access with v16. I am curious if my new v16.31 license code from Mentor Graphics will still work with v15.23? I have downloaded but not installed yet.