Even FLS5 uses AFDKO 1.6 for compiling layout tables. From FontLab's font editors, only the new FOG5 uses AFDKO 2.5.

FL has said that when FLS6 comes out, it will use AFDKO 2.5

What exactly do you want to do? Using AFDKO 2.5 (makeotf.exe) to build an OpenType font from a Type 1 font generated by FontLab Studio should be possible with any version.

You would have to install AFDKO separately and use it outside of FontLab Studio in that case.

I think maybe he wants to use the AFDKO 2.5 FontLab macros in FL 4.6. I don't know if that's possible, but it seems like it could be. I couldn't find any mention in the documentation of which FL version is required. In the macro installation script, it shows where to put the macros if one is using FLS5/Mac, which seems to imply that you need FLS5. Or maybe not.

I would say that the AFDKO 2.5 FontLab macros *might* work in FontLab 4.6, but there is no guarantee. I suppose Adobe never tested that situation, and never made a claim that those macros would work in FontLab 4.6. But the Python API in FontLab Studio 5 is a straight extension of that in FontLab 4.6, and many macros work in both versions.

Thank you all for your input. What I am needing to do is add mark to base and mark to mark open type features in a right-to-left font. I know this needs to be done in VOLT or AFDKO which both are new to me. Since I work on Mac I was going to try AFDKO but have not updated to FontLab Studio 5 and in all I’ve read a version of FontLab wasn’t specified.

You can't do that kind of stuff from within FontLab Studio 5 anyway, even with AFDKO 2.5 and its macros installed. However, you can use AFDKO 2.5 outside of FontLab from the command line. You'll need to write your features as text files. It's all explained in the AFDKO documentation.

If you don't like commandline, you can get Fontographer 5. You can open your FontLab VFBs, point to an AFDKO 2.5 feature definition file, and generate your OTF or TTF from there. The standalone AFDKO 2.5 only builds OTF fonts. Fontographer 5.0 has AFDKO 2.5 integrated but is also able to generate TTF fonts. FontLab Studio 5 only has AFDKO 1.6 integrated, which does not have mark support.