diff --git a/doc/0-INSTALL.mkd b/doc/0-INSTALL.mkd
index 37c81cc..a110431 100644
--- a/doc/0-INSTALL.mkd
+++ b/doc/0-INSTALL.mkd
@@ -173,14 +173,6 @@ just work without any change; you should not normally have to do anything
 special.  However, some new features may require additional settings in your
 `~/.gitolite.rc` file.
 
->   [The only exception to this is when there is a change in the format of the
-"compiler" output -- then *each* gitolite hosting user must run "`gl-setup`
-again (no arguments needed this time), to fix up the compiled file format.
-
->   Such a change will be clearly marked with "upgrade notes" both in the
-CHANGELOG and in the commit message.  For example, this applies when upgrading
-to v1.5 or later from any version before it.]
-
 Finally, in the rare case that you managed to lose your keys to the admin repo
 and want to supply a new pubkey, you can use this command to replace any such
 key.  Could be useful in an emergency -- just get your new "yourname.pub" to
diff --git a/doc/CHANGELOG b/doc/CHANGELOG
index de1cd01..fdfd39f 100644
--- a/doc/CHANGELOG
+++ b/doc/CHANGELOG
@@ -2,13 +2,16 @@ Major changes to gitolite, master branch only, most recent first, no dates but
 the tags can help you position stuff approximately
 [NYD = not yet documented due to lack of time...]
 
+  - v1.5.1 -- tries to eliminate the need to run gl-setup on data version
+    change, thus hopefully obsoleting the upgrade note for v1.5 (just below).
+
   - v1.5 -- IMPORTANT UPGRADE NOTES below
 
-Upgrading to v1.5 from any version prior to v1.5 requires an extra step for
-people who installed gitolite using the "system install / user setup" method
-described in doc/0-INSTALL.mkd.  For such installations, after the
-administrator has upgraded gitolite system-wide, each "gitolite host" user
-must run `gl-setup` once (this time without any arguments).
+    Upgrading to v1.5 from any version prior to v1.5 requires an extra step
+    for people who installed gitolite using the "system install / user setup"
+    method described in doc/0-INSTALL.mkd.  For such installations, after the
+    administrator has upgraded gitolite system-wide, each "gitolite host" user
+    must run `gl-setup` once (this time without any arguments).
 
   - "deny" rules should now work even in "big-config" due to previous change
   - proper rule sequencing (required major format change)
diff --git a/src/gitolite.pm b/src/gitolite.pm
index fcc122f..bdc0db8 100644
--- a/src/gitolite.pm
+++ b/src/gitolite.pm
@@ -40,6 +40,8 @@ our $REPOPATT_PATT=qr(^\@?[0-9a-zA-Z][\\^.$|()[\]*+?{}0-9a-zA-Z._\@/-]*$);
 our ($REPO_UMASK, $GL_WILDREPOS, $GL_PACKAGE_CONF, $GL_PACKAGE_HOOKS, $REPO_BASE, $GL_CONF_COMPILED, $GL_BIG_CONFIG);
 our %repos;
 our %groups;
+our $data_version;
+our $current_data_version = '1.5';
 
 # ----------------------------------------------------------------------------
 #       convenience subs
@@ -253,6 +255,13 @@ sub parse_acl
     our $gl_user = $ENV{GL_USER};
 
     die "parse $GL_CONF_COMPILED failed: " . ($! or $@) unless do $GL_CONF_COMPILED;
+    unless (defined($data_version) and $data_version eq $current_data_version) {
+        # this cannot happen for 'easy-install' cases, by the way...
+        print STDERR "(INTERNAL: $data_version -> $current_data_version; running gl-setup)\n";
+        system("$ENV{SHELL} -l gl-setup >&2");
+
+        die "parse $GL_CONF_COMPILED failed: " . ($! or $@) unless do $GL_CONF_COMPILED;
+    }
 
     # basic access reporting doesn't send $repo, and doesn't need to; you just
     # want the config dumped as is, really
diff --git a/src/gl-compile-conf b/src/gl-compile-conf
index 63a677c..1d910db 100755
--- a/src/gl-compile-conf
+++ b/src/gl-compile-conf
@@ -103,6 +103,8 @@ my $rule_seq = 0;
 # multiple times for the same repo+user.  So...
 my %rurp_seen = ();
 
+our $current_data_version;      # this comes from gitolite.pm
+
 # catch usernames<->pubkeys mismatches; search for "lint" below
 my %user_list = ();
 
@@ -372,6 +374,8 @@ for my $fragment_file (glob("conf/fragments/*.conf"))
 }
 
 my $compiled_fh = wrap_open( ">", $GL_CONF_COMPILED );
+my $data_version = $current_data_version;
+print $compiled_fh Data::Dumper->Dump([$data_version], [qw(*data_version)]);
 my $dumped_data = Data::Dumper->Dump([\%repos], [qw(*repos)]);
 # the dump uses single quotes, but we convert any strings containing $creator,
 # $readers, $writers, to double quoted strings.  A wee bit sneaky, but not too