diff --git a/src/libexchangemapi/tz-ical-to-mapi b/src/libexchangemapi/tz-ical-to-mapi
index 64d97cd..16b1371 100644
--- a/src/libexchangemapi/tz-ical-to-mapi
+++ b/src/libexchangemapi/tz-ical-to-mapi
@@ -1,4 +1,4 @@
-UTC~~~GMT Standard Time
+UTC~~~UTC
 Africa/Abidjan~~~Greenwich Standard Time
 Africa/Accra~~~Greenwich Standard Time
 Africa/Addis_Ababa~~~E. Africa Standard Time
diff --git a/src/libexchangemapi/tz-mapi-to-ical b/src/libexchangemapi/tz-mapi-to-ical
index a09ab98..6711d74 100644
--- a/src/libexchangemapi/tz-mapi-to-ical
+++ b/src/libexchangemapi/tz-mapi-to-ical
@@ -30,7 +30,8 @@ Mid-Atlantic Standard Time~~~Atlantic/South_Georgia
 Azores Standard Time~~~Atlantic/Azores
 Cape Verde Standard Time~~~Atlantic/Cape_Verde
 Greenwich Standard Time~~~Africa/Casablanca
-GMT Standard Time~~~UTC
+GMT Standard Time~~~Europe/Dublin
+UTC~~~UTC
 W. Europe Standard Time~~~Europe/Berlin
 Central Europe Standard Time~~~Europe/Prague
 Romance Standard Time~~~Europe/Paris
