+my($vs, $ss) = ("x" x 100, "x" x 100); # allocate space for these strings
+my $version = Net::Z3950::ZOOM::yaz_version($vs, $ss);
+if ($version < 0x02010B && ! -f "/tmp/ignore-ZOOM-YAZ-version-mismatch") {
+ warn <<__EOT__;
+*** WARNING!
+ZOOM-Perl requires at least version 2.0.11 of YAZ, but is currently
+running against only version $vs (sys-string '$ss').
+Some things may not work.
+__EOT__
+}