diff --git a/build-constraints.yaml b/build-constraints.yaml
index 647f81cc..3d2e781f 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -561,8 +561,8 @@ packages:
         - tasty-smallcheck
         - tasty-html
         - time-lens
-        # GHC 8 - timezone-olson
-        # GHC 8 - timezone-series
+        - timezone-olson
+        - timezone-series
         - traverse-with-class
         - tuples-homogenous-h98
 
@@ -2047,7 +2047,7 @@ packages:
 
     "Mihaly Barasz klao@nilcons.com @klao":
         - lens-datetime
-        # via timezone-olson - tz
+        - tz
         - tzdata
 
     "Timothy Klim <stackage@timothyklim.com> @TimothyKlim":