doc/doc-txt/IncompatibleChanges

   1 Preamble
   2 ========
   3
   4 Normally The Exim Maintainers ensure that a configuration which works
   5 with version N will work with version N+1, within a major version number
   6 (eg, 4).
   7
   8 Occasionally this will not be the case; usually, those changes will be
   9 at the end of a long notice period where admins have been encouraged to
  10 move away and even then, we are hesitant to fully break things without
  11 strong cause to move away.
  12
  13 This does not apply to "experimental" features, which can be withdrawn
  14 or changed with little notice, although we still endeavour to limit
  15 that.  We may choose to note those changes here too.
  16
  17 The most likely cause of a backwards-incompatible change is a security
  18 improvement, where the benefits for everyone strongly outweigh the needs
  19 of the few.
  20
  21
  22 Changes
  23 =======
  24
  25 Exim version 4.73
  26 -----------------
  27
  28  * The Exim run-time user can no longer be root; this was always
  29    strongly discouraged, but is now prohibited both at build and
  30    run-time.  If you need Exim to run routinely as root, you'll need to
  31    patch the source and accept the risk.  Here be dragons.
  32
  33  * Exim will no longer accept a configuration file owned by the Exim
  34    run-time user, unless that account is explicitly the value in
  35    CONFIGURE_OWNER, which we discourage.  Exim now checks to ensure that
  36    files are not writable by other accounts.
  37
  38  * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced
  39    on; the Exim user can, by default, no longer use -C/-D and retain privilege.
  40    Two new build options mitigate this.
  41
  42     * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config
  43       files that are trusted to be selected by the Exim user; this is the
  44       recommended approach going forward.
  45
  46     * WHITELIST_D_MACROS defines a colon-separated list of macro names which
  47       the Exim run-time user may safely pass without dropping privileges.
  48       Because changes to this involve a recompile, this is not the recommended
  49       approach but may ease transition.  The values of the macros, when
  50       overriden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$
  51
  52  * The system_filter_user option now defaults to the Exim run-time user,
  53    rather than root.  You can still set it explicitly to root and this
  54    can be done with prior versions too, letting you roll versions
  55    without needing to change this configuration option.
  56
  57  * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is
  58    defined at build time.
  59