Spectre Can write output data to fsdb format, but format is new.
I need to translate FSDB 4.xx (5.xx) to fsdb 2.3.
The program, which I use, read only (2.3) format.
If there is no program-translator, where I can look FSDB file format specification (2.3, 4.xx, 5.xx)
FSDB is not a Cadence file format, so we don't provide tools to read it, nor do we document the format. I believe it is owned by Synopsys now, so probably best to ask them.