diff --git a/IkiWiki/Plugin/po.pm b/IkiWiki/Plugin/po.pm
index 193cf0a54..8f169fda5 100644
--- a/IkiWiki/Plugin/po.pm
+++ b/IkiWiki/Plugin/po.pm
@@ -828,7 +828,7 @@ sub refreshpofiles ($@) {
 	foreach my $pofile (@pofiles) {
 		IkiWiki::prep_writefile(basename($pofile),dirname($pofile));
 		if (-e $pofile) {
-			system("msgmerge", "-q", "-U", "--backup=none", $pofile, $potfile) == 0
+			system("msgmerge", "--previous", "-q", "-U", "--backup=none", $pofile, $potfile) == 0
 				or error("po(refreshpofiles) ".
 					 sprintf(gettext("failed to update %s"),
 						 $pofile));