This is a list of features that are scheduled to be removed from dpkg.

What: fallback of dpkg-source to source format "1.0" without explicit debian/source/format
Status: deprecated
When: 1.17.x
Warning: program and lintian (missing-debian-source-format)
Why:
 With the support of multiple source formats, the user should be explicit
 about the desired source format. The fallback to "1.0" is there only for
 backwards compatibility but will be removed once all packages have the
 debian/source/format file. This is unlikely to happen before 1.17.x.

What: Source-Version (substvar)
Status: obsolete
When: 1.16.x
Warning: lintian (substvar-source-version-is-deprecated)
Why:
 The semantics of Source-Version are missleading when applied to binNMUs.
 Should switch to use binary:Version or source:Version substvars.

What: Revision, Package-Revision, Package_Revision, Class, Recommended,
      Optional (field)
Status: obsolete
When: 1.15.x
Warning: program
Why:
 These fields have been superseded by either other fields with better names
 or values in other fields.

What: -u, --udeb (dpkg-scanpackages option)
Status: deprecated
When: 1.16.x
Warning: program
Why:
 This option has been superseded by -tudeb.

What: support of PGP
Status: deprecated
When: 1.15.x
Warning: program
Why:
 PGP is not part of Debian and GnuPG has been the standard tool for digital
 signatures for several years already. Supporting only GnuPG enables us to
 rely on some of its features.

What: --print-installation-architecture (dpkg option)
Status: obsolete
When: 1.15.x
Warning: program
Why:
 Obsoleted long time ago (2005-01-22). Remaining packages should switch to
 use 'dpkg --print-architecture'.

What --forget-old-unavail (dpkg option)
Status: obsolete
When: 1.16.x
Warning: program
Why:
 Purged packages are properly cleaned up now by dpkg, and old unavailable
 leftovers are automatically cleaned up on database parsing. So there's no
 need anymore for this manual action.

History of feature removals
~~~~~~~~~~~~~~~~~~~~~~~~~~~

What: cleanup-info (program)
Status: removed
Since: 1.15.0
Why:
 This program was needed long time ago to fixup broken info dir files
 generated by buggy install-info programs. Should not be needed anymore.

What: --largemem, --smallmem (dpkg option)
Status: removed
When: 1.15.1
Why:
 These options have been no-ops for a long time.

What: --force-auto-select (dpkg option)
Status: removed
When: 1.15.1
Why:
 This option has been a no-op for so long, that there's no traces on git
 history of its usage.

What: recommended, contrib, base (priority)
Status: removed
When: 1.15.1
Why:
 These priorities have been superseded by either other fields or values in
 other fields.

What: 822-date (program)
Status: removed
When: 1.15.1
Why:
 Should switch to use 'date -R'.

What: support of custom changelog parsers understanding only -v
Status: removed
Since: 1.15.5
Why:
 The debian changelog parser has been enhanced. It supports new options
 that enable more fine-grained retrieval of information. Those new options
 will be used by scripts (like dpkg-genchanges).
 .
 Custom changelog parsers must be updated to support the new API (see
 dpkg-parsechangelog(1) and README.api).

What: support for environment variable DPKG_NO_TSTP
Status: removed
Since: 1.15.6
Why:
 Having two ways to let the administrator get to a shell on conffile prompt
 is confusing, it also difficults setting up a consistent environment to be
 used by external programs.