INSTALL                         | 24 ++++++++++++++----------
 lib/PublicInbox/WatchMaildir.pm |  2 ++
 t/watch_maildir.t               |  5 +++++

diff --git a/INSTALL b/INSTALL
index e7d4b752224b1d7d206a0ca51e859553b182a63c..7f12fbec97f16fc5d2343bc92555574ad8cc52e2 100644
--- a/INSTALL
+++ b/INSTALL
@@ -19,8 +19,8 @@ 	make
 	make test
 	make install # root permissions may be needed
 
-Requirements (server MDA)
--------------------------
+Requirements
+------------
 
 * git
 * SpamAssassin (spamc/spamd)
@@ -36,19 +36,23 @@
   - Plack[1]                   libplack-perl
   - Mail::Thread (2.5+)[1]     libmail-thread-perl
   - URI::Escape[1]             liburi-perl
-  - Search::Xapian[3]          libsearch-xapian-perl
-  - IO::Compress::Gzip[3]      libio-compress-perl
+  - Search::Xapian[2][3]       libsearch-xapian-perl
+  - IO::Compress::Gzip[3]      perl-modules (or libio-compress-perl)
   - DBI[3]                     libdbi-perl
-  - DBD::SQLite[3]             libdbd-sqlite3-perl
+  - DBD::SQLite[2][3]          libdbd-sqlite3-perl
   - Danga::Socket[4]           libdanga-socket-perl
-  - Net::Server[4]             libnet-server-perl
+  - Net::Server[5]             libnet-server-perl
+  - Filesys::Notify::Simple[6] libfilesys-notify-simple-perl
 
-[1] - Only required for serving/generating Atom and HTML pages.
-[3] - Optional for HTML web interface and HTTP/NNTP servers
-[4] - Optional for HTTP and NNTP servers
+[1] - Optional, needed for serving/generating Atom and HTML pages
+[2] - Optional, only required for NNTP server
+[3] - Optional, needed for gzipped mbox support over HTTP
+[4] - Optional, needed for bundled HTTP and NNTP servers
+[5] - Optional, needed for standalone daemonization of HTTP+NNTP servers
+[6] - Optional, needed for public-inbox-watch Maildir watcher
 
 When installing Search::Xapian, make sure the underlying Xapian
-is patched against the index corruption bug documented in:
+installation is not affected by an index corruption bug:
 
 	https://bugs.debian.org/808610
 
diff --git a/lib/PublicInbox/WatchMaildir.pm b/lib/PublicInbox/WatchMaildir.pm
index 4468a4484fd63dfdbca81aa3bf193fd48a3f4c89..abf1df7bab32b533aa209e6f01999646a6be5767 100644
--- a/lib/PublicInbox/WatchMaildir.pm
+++ b/lib/PublicInbox/WatchMaildir.pm
@@ -144,6 +144,8 @@ 	my ($self) = @_;
 	my $cb = sub { _try_fsn_paths($self, \@_) };
 	my $mdir = $self->{mdir};
 
+	# lazy load here, we may support watching via IMAP IDLE
+	# in the future...
 	require Filesys::Notify::Simple;
 	my $watcher = Filesys::Notify::Simple->new($mdir);
 	$watcher->wait($cb) while (1);
diff --git a/t/watch_maildir.t b/t/watch_maildir.t
index e8c97406eb59e976aec3056af96ef57f027c07ed..be1a31285bbefd295722b3b9457f8ebf9256db16 100644
--- a/t/watch_maildir.t
+++ b/t/watch_maildir.t
@@ -4,6 +4,11 @@ use Test::More;
 use File::Temp qw/tempdir/;
 use Email::MIME;
 use PublicInbox::Config;
+my @mods = qw(Filesys::Notify::Simple);
+foreach my $mod (@mods) {
+	eval "require $mod";
+	plan skip_all => "$mod missing for watch_maildir.t" if $@;
+}
 
 my $tmpdir = tempdir('watch_maildir-XXXXXX', TMPDIR => 1, CLEANUP => 1);
 my $git_dir = "$tmpdir/test.git";