doc: drop note about early versions of Xapian

Mathias Beyer [1] points out that this note is redudant since Xapian
no longer builds with the problematic versions of Xapian.

[1]: id:20210207124404.yldgtzjrsagacrl4@hoshi

diff --git a/INSTALL b/INSTALL
index 40ea377af97d6b72325016044a8db37433671d3e..7479a4b67a71c6b2bd66ea8ae16d866550ba33fb 100644 (file)
--- a/INSTALL
+++ b/INSTALL
@@ -32,13 +32,6 @@ Talloc, and zlib which are each described below:
 
        Xapian is available from https://xapian.org
 
-       Note: Notmuch will work best with Xapian 1.0.18 (or later) or
-       Xapian 1.1.4 (or later). Previous versions of Xapian (whether
-       1.0 or 1.1) had a performance bug that made notmuch very slow
-       when modifying tags. This would cause distracting pauses when
-       reading mail while notmuch would wait for Xapian when removing
-       the "inbox" and "unread" tags from messages in a thread.
-
        GMime
        -----
        GMime provides decoding of MIME email messages for Notmuch.