will songs recorded on Cubase 4 open in Cubase 5?

The subject line pretty much sums up my question. I have some tracks recorded on Cubase 4, and may install Cubase 5, but , I thought I read somewhere that one couldn’t open songs recorded in earlier versions of Cubase on Cubase 5. True?

will songs recorded on Cubase 4 open in Cubase 5?

Yes.

Thanks so much. Are the effects different?

There are some added effects in 5. Much of 4’s effects remain. Just about any of the effects can be downloaded from Steinberg’s archive section.
If you open your songs in 5, they will no longer work in 4 so if you intend to do so, make a separate copy of the song before you save it in 5.