diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,10 @@
 # Changelog for timezone-detect
 
+## v0.3.0.1 (2021-03-14)
+
+* Adds property tests.
+* Updates base to work with newer versions of Haskell.
+
 ## v0.3.0.0 (2020-09-02)
 
 **Breaking Changes!**
diff --git a/test/TimezoneDetectSpec.hs b/test/TimezoneDetectSpec.hs
--- a/test/TimezoneDetectSpec.hs
+++ b/test/TimezoneDetectSpec.hs
@@ -3,6 +3,8 @@
 import Data.Time
 import Data.Time.LocalTime.TimeZone.Detect
 import Test.Hspec
+import Test.QuickCheck (oneof, choose, forAll, Gen)
+import Data.Maybe (isNothing, isJust)
 
 zoneFile :: FilePath
 zoneFile = "./test/tz_db/timezone21.bin"
@@ -66,6 +68,14 @@
                 let bogus = lookupTimeZoneName badDb 40.7831 (-73.9712)
                 bogus `shouldBe` Nothing
 
+            it "finds a timezone name for any latitude and longitude on Earth" $ \db -> do
+                forAll genCoords $ \(a,b) ->
+                    isJust $ lookupTimeZoneName db a b
+
+            it "fails for any invalid set of coordinates" $ \db -> do
+                forAll genBadCoords $ \(a,b) ->
+                    isNothing $ lookupTimeZoneName db a b
+
         describe "timeAtPointToUTC" $ do
             it "calculates a UTC instant at a point in time and space in New York" $ \db -> do
                 localWinter <- localTimeFromString "2019-12-25 00:30:00"
@@ -90,3 +100,15 @@
 
                 atPointWinter `shouldBe` utcWinter
                 atPointSummer `shouldBe` utcSummer
+
+genCoords :: Gen (Double, Double)
+genCoords = do
+    lat <- choose (-90.0, 90.0)
+    lng <- choose (-180.0, 180.0)
+    return (lat, lng)
+
+genBadCoords :: Gen (Double, Double)
+genBadCoords = do
+    lat <- oneof [choose (-360, -90), choose (90, 360)]
+    lng <- oneof [choose (-360, -180), choose (180, 360)]
+    return (lat, lng)
diff --git a/timezone-detect.cabal b/timezone-detect.cabal
--- a/timezone-detect.cabal
+++ b/timezone-detect.cabal
@@ -4,10 +4,10 @@
 --
 -- see: https://github.com/sol/hpack
 --
--- hash: cada8fe310ed1ed1c85911dc9e3b40c06e5e111b2984429f42aa5a762a956c9a
+-- hash: 400585ad246f3ace6cd8038f78ddcb944512b6fc8a0756c20ba915afa995d67e
 
 name:           timezone-detect
-version:        0.3.0.0
+version:        0.3.0.1
 synopsis:       Haskell bindings for the zone-detect C library; plus tz-aware utils.
 description:    Please see the README on GitHub at <https://github.com/lfborjas/timezone-detect#readme>
 category:       Data, Foreign, Time
@@ -42,7 +42,7 @@
   c-sources:
       csrc/zonedetect.c
   build-depends:
-      base >=4.9 && <4.14
+      base >=4.9 && <=4.15
     , time >=1.9.1 && <=1.10
     , timezone-olson >=0.2.0 && <0.3
     , timezone-series >=0.1.0 && <0.2
@@ -60,7 +60,8 @@
   build-tool-depends:
       hspec-discover:hspec-discover >=2.7 && <2.8
   build-depends:
-      base >=4.9 && <4.14
+      QuickCheck >=2.12 && <=2.14
+    , base >=4.9 && <=4.15
     , directory >=1.3 && <1.4
     , hspec >=2.7 && <2.8
     , time >=1.9.1 && <=1.10