I think, libtiff 4.0 was released. http://www.remotesensing.org/libtiff/ http://download.osgeo.org/libtiff/ although it contradicts http://www.libtiff.org/
"Announcing Libtiff 4.0.0", by Bob Friesenhahn At long last, libtiff 4.0.0 is finally released. Libtiff 4.0.0 is the successor to the libtiff 3.9.X release series. It is intended to be largely API compatible with the 3.9.X releases, but it is definitely not ABI compatible so any software which plans to use it will need to be recompiled. With appropriate care, source code can easily compile with both the 3.9.X releases and libtiff 4.0.0. This release supports the BigTIFF TIFF format in which all offsets are unsigned 64-bit, supporting huge files. APIs which deal with tag offsets are necessarily updated to pass 64-bit values. I/O functions supporting the TIFFClientOpen() interface are updated to pass 64-bit offset values. Complete changelog: http://www.remotesensing.org/libtiff/v4.0.0.html
Just FYI, I'm waiting on 4.0.1 before doing anything about this. It's too late to consider it for F-17 in any case.
4.0.1 is here.