Get specific version macports dependencies
That looks like either a bug or a limitation with the deps command to me. A quick look in the MacPorts Guide, and port help deps doesn't specify any such limitation, though that's not very conclusive.

I'm not sure if you should be able to see dependencies for different versions, though I can definitely see different dependencies for different variants.

I have two versions of boost installed (note the different python variants, but same version):

% port installed boost
The following ports are currently installed:
  boost @1.54.0_0+no_single+no_static+python27 (active)
  boost @1.54.0_0+no_single+no_static+python33


And I can check their dependencies independently by referencing them as portname@version+variants (version &amp; variants being optional):

% port deps boost @1.54.0_0+no_single+no_static+python27
Full Name: boost @1.54.0_0+no_single+no_static+python27
Library Dependencies: zlib, expat, bzip2, libiconv, icu, python27

% port deps boost @1.54.0_0+no_single+no_static+python33
Full Name: boost @1.54.0_0+no_single+no_static+python33
Library Dependencies: zlib, expat, bzip2, libiconv, icu, python33


But I also have two versions of glib2 and pango installed at present:

% port installed glib2 pango
The following ports are currently installed:
  glib2 @2.36.4_0
  glib2 @2.38.0_0 (active)
  pango @1.34.1_1+x11
  pango @1.36.0_0+x11 (active)


Yet, likewise, cannot see the deps of the inactive versions:

% port deps glib2 @2.36.4_0
Full Name: glib2 @2.38.0_1
Extract Dependencies: xz
Build Dependencies:   libxml2
Library Dependencies: gettext, libiconv, zlib, libffi, perl5

% port deps pango @1.34.1_1+x11
Full Name: pango @1.36.0_0+x11
Extract Dependencies: xz
Build Dependencies:   pkgconfig
Library Dependencies: glib2, cairo, gobject-introspection, harfbuzz, Xft2


Both show the newer (active) version rather than the older one, even with the --index argument to deps.