diff --git a/src/libraries/Common/tests/CoreFx.Private.TestUtilities/System/PlatformDetection.Unix.cs b/src/libraries/Common/tests/CoreFx.Private.TestUtilities/System/PlatformDetection.Unix.cs
index b4a7c5638903e3..58aa95010c0954 100644
--- a/src/libraries/Common/tests/CoreFx.Private.TestUtilities/System/PlatformDetection.Unix.cs
+++ b/src/libraries/Common/tests/CoreFx.Private.TestUtilities/System/PlatformDetection.Unix.cs
@@ -17,14 +17,12 @@ public static partial class PlatformDetection
         //
 
         private static bool IsLinux => RuntimeInformation.IsOSPlatform(OSPlatform.Linux);
-        public static bool IsCentos6 => IsDistroAndVersion("centos", 6);
         public static bool IsOpenSUSE => IsDistroAndVersion("opensuse");
         public static bool IsUbuntu => IsDistroAndVersion("ubuntu");
         public static bool IsDebian => IsDistroAndVersion("debian");
         public static bool IsAlpine => IsDistroAndVersion("alpine");
         public static bool IsDebian8 => IsDistroAndVersion("debian", 8);
         public static bool IsDebian10 => IsDistroAndVersion("debian", 10);
-        public static bool IsUbuntu1404 => IsDistroAndVersion("ubuntu", 14, 4);
         public static bool IsUbuntu1604 => IsDistroAndVersion("ubuntu", 16, 4);
         public static bool IsUbuntu1704 => IsDistroAndVersion("ubuntu", 17, 4);
         public static bool IsUbuntu1710 => IsDistroAndVersion("ubuntu", 17, 10);
diff --git a/src/libraries/Common/tests/System/Drawing/Helpers.cs b/src/libraries/Common/tests/System/Drawing/Helpers.cs
index 1b41f92c8c939a..897501f22927bd 100644
--- a/src/libraries/Common/tests/System/Drawing/Helpers.cs
+++ b/src/libraries/Common/tests/System/Drawing/Helpers.cs
@@ -59,8 +59,8 @@ public static bool GetIsWindowsOrAtLeastLibgdiplus6()
 
         public static bool GetRecentGdiPlusIsAvailable2()
         {
-            // RedHat and Ubuntu 14.04, as well as Fedora 25 and OpenSUSE 4.22 are running outdated versions of libgdiplus
-            if (PlatformDetection.IsRedHatFamily || PlatformDetection.IsUbuntu1404 || PlatformDetection.IsFedora || PlatformDetection.IsOpenSUSE)
+            // RedHat as well as Fedora 25 and OpenSUSE 4.22 are running outdated versions of libgdiplus
+            if (PlatformDetection.IsRedHatFamily || PlatformDetection.IsFedora || PlatformDetection.IsOpenSUSE)
             {
                 return false;
             }
@@ -90,8 +90,8 @@ public static bool GetGdiPlusIsAvailableNotWindows7()
 
         public static bool GetRecentGdiPlusIsAvailable()
         {
-            // RedHat and Ubuntu 14.04 are running outdated versions of libgdiplus
-            if (PlatformDetection.IsRedHatFamily || PlatformDetection.IsUbuntu1404)
+            // RedHat is running outdated versions of libgdiplus
+            if (PlatformDetection.IsRedHatFamily)
             {
                 return false;
             }
diff --git a/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetAbbreviatedDayName.cs b/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetAbbreviatedDayName.cs
index 0214b34c39c20d..6ed8197dd88ced 100644
--- a/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetAbbreviatedDayName.cs
+++ b/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetAbbreviatedDayName.cs
@@ -16,7 +16,7 @@ public static IEnumerable<object[]> GetAbbreviatedDayName_TestData()
             yield return new object[] { new CultureInfo("en-US").DateTimeFormat, englishAbbreviatedDayNames };
             yield return new object[] { new DateTimeFormatInfo(), englishAbbreviatedDayNames };
 
-            if (!PlatformDetection.IsUbuntu || PlatformDetection.IsUbuntu1404)
+            if (!PlatformDetection.IsUbuntu)
             {
                 yield return new object[] { new CultureInfo("fr-FR").DateTimeFormat, DateTimeFormatInfoData.FrFRAbbreviatedDayNames() };
             }
diff --git a/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetAbbreviatedMonthName.cs b/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetAbbreviatedMonthName.cs
index 97a8621ed3349a..433b6ee72acafd 100644
--- a/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetAbbreviatedMonthName.cs
+++ b/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetAbbreviatedMonthName.cs
@@ -19,7 +19,7 @@ public static IEnumerable<object[]> GetAbbreviatedMonthName_TestData()
             yield return new object[] { new CultureInfo("en-US").DateTimeFormat, englishAbbreviatedMonthNames };
             yield return new object[] { new DateTimeFormatInfo(), englishAbbreviatedMonthNames };
 
-            if (!PlatformDetection.IsUbuntu || PlatformDetection.IsUbuntu1404)
+            if (!PlatformDetection.IsUbuntu)
             {
                 yield return new object[] { new CultureInfo("fr-FR").DateTimeFormat, new string[] { "", "janv.", "f\u00E9vr.", "mars", "avr.", "mai", "juin", "juil.", "ao\u00FBt", "sept.", "oct.", "nov.", "d\u00E9c.", "" } };
             }
diff --git a/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetDayName.cs b/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetDayName.cs
index bf1405a7fba941..37ea97586425a6 100644
--- a/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetDayName.cs
+++ b/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetDayName.cs
@@ -17,7 +17,7 @@ public static IEnumerable<object[]> GetDayName_TestData()
             yield return new object[] { new CultureInfo("en-US").DateTimeFormat, englishDayNames };
             yield return new object[] { new DateTimeFormatInfo(), englishDayNames };
 
-            if (!PlatformDetection.IsUbuntu || PlatformDetection.IsUbuntu1404)
+            if (!PlatformDetection.IsUbuntu)
             {
                 yield return new object[] { new CultureInfo("fr-FR").DateTimeFormat, DateTimeFormatInfoData.FrFRDayNames() };
             }
diff --git a/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetMonthName.cs b/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetMonthName.cs
index 77e3e4cff0b56c..fd2e1f8f10537a 100644
--- a/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetMonthName.cs
+++ b/src/libraries/System.Globalization/tests/DateTimeFormatInfo/DateTimeFormatInfoGetMonthName.cs
@@ -19,7 +19,7 @@ public static IEnumerable<object[]> GetMonthName_TestData()
             yield return new object[] { new DateTimeFormatInfo(), englishMonthNames };
             yield return new object[] { new CultureInfo("en-US").DateTimeFormat, englishMonthNames };
 
-            if (!PlatformDetection.IsUbuntu || PlatformDetection.IsUbuntu1404)
+            if (!PlatformDetection.IsUbuntu)
             {
                 yield return new object[] { new CultureInfo("fr-FR").DateTimeFormat, new string[] { "", "janvier", "f\u00E9vrier", "mars", "avril", "mai", "juin", "juillet", "ao\u00FBt", "septembre", "octobre", "novembre", "d\u00E9cembre", "" } };
             }
diff --git a/src/libraries/System.Globalization/tests/NumberFormatInfo/NumberFormatInfoCurrencyGroupSizes.cs b/src/libraries/System.Globalization/tests/NumberFormatInfo/NumberFormatInfoCurrencyGroupSizes.cs
index 60b211d7af882a..3dd9f5acef5c0f 100644
--- a/src/libraries/System.Globalization/tests/NumberFormatInfo/NumberFormatInfoCurrencyGroupSizes.cs
+++ b/src/libraries/System.Globalization/tests/NumberFormatInfo/NumberFormatInfoCurrencyGroupSizes.cs
@@ -14,8 +14,7 @@ public static IEnumerable<object[]> CurrencyGroupSizes_TestData()
             yield return new object[] { NumberFormatInfo.InvariantInfo, new int[] { 3 } };
             yield return new object[] { CultureInfo.GetCultureInfo("en-US").NumberFormat, new int[] { 3 } };
 
-            if ((!PlatformDetection.IsUbuntu || PlatformDetection.IsUbuntu1404)
-                && !PlatformDetection.IsWindows7 && !PlatformDetection.IsWindows8x && !PlatformDetection.IsFedora)
+            if (!PlatformDetection.IsUbuntu && !PlatformDetection.IsWindows7 && !PlatformDetection.IsWindows8x && !PlatformDetection.IsFedora)
             {
                 yield return new object[] { CultureInfo.GetCultureInfo("ur-IN").NumberFormat, new int[] { 3, 2 } };
             }
diff --git a/src/libraries/System.Security.Cryptography.X509Certificates/tests/PfxTests.cs b/src/libraries/System.Security.Cryptography.X509Certificates/tests/PfxTests.cs
index 0047336784b8bc..6a44f255b34758 100644
--- a/src/libraries/System.Security.Cryptography.X509Certificates/tests/PfxTests.cs
+++ b/src/libraries/System.Security.Cryptography.X509Certificates/tests/PfxTests.cs
@@ -249,9 +249,9 @@ public static void ReadECDsaPrivateKey_BrainpoolP160r1_Pfx(byte[] pfxData)
             }
             catch (CryptographicException)
             {
-                // Windows 7, Windows 8, Ubuntu 14, CentOS, macOS can fail. Verify known good platforms don't fail.
+                // Windows 7, Windows 8, CentOS, macOS can fail. Verify known good platforms don't fail.
                 Assert.False(PlatformDetection.IsWindows && PlatformDetection.WindowsVersion >= 10, "Is Windows 10");
-                Assert.False(PlatformDetection.IsUbuntu && !PlatformDetection.IsUbuntu1404, "Is Ubuntu 16.04 or up");
+                Assert.False(PlatformDetection.IsUbuntu, "Is Ubuntu");
             }
         }
 
diff --git a/src/libraries/System.Security.Cryptography.X509Certificates/tests/PublicKeyTests.cs b/src/libraries/System.Security.Cryptography.X509Certificates/tests/PublicKeyTests.cs
index 29bed54e83851c..3b3e4f97f34105 100644
--- a/src/libraries/System.Security.Cryptography.X509Certificates/tests/PublicKeyTests.cs
+++ b/src/libraries/System.Security.Cryptography.X509Certificates/tests/PublicKeyTests.cs
@@ -330,9 +330,9 @@ public static void TestKey_ECDsabrainpool_PublicKey(byte[] curveData, byte[] not
             }
             catch (CryptographicException)
             {
-                // Windows 7, Windows 8, Ubuntu 14, CentOS can fail. Verify known good platforms don't fail.
+                // Windows 7, Windows 8, CentOS can fail. Verify known good platforms don't fail.
                 Assert.False(PlatformDetection.IsWindows && PlatformDetection.WindowsVersion >= 10);
-                Assert.False(PlatformDetection.IsUbuntu && !PlatformDetection.IsUbuntu1404);
+                Assert.False(PlatformDetection.IsUbuntu);
             }
         }
 
@@ -420,9 +420,9 @@ public static void TestECDsaPublicKey_BrainpoolP160r1_ValidatesSignature(byte[]
             }
             catch (CryptographicException)
             {
-                // Windows 7, Windows 8, Ubuntu 14, CentOS can fail. Verify known good platforms don't fail.
+                // Windows 7, Windows 8, CentOS can fail. Verify known good platforms don't fail.
                 Assert.False(PlatformDetection.IsWindows && PlatformDetection.WindowsVersion >= 10);
-                Assert.False(PlatformDetection.IsUbuntu && !PlatformDetection.IsUbuntu1404);
+                Assert.False(PlatformDetection.IsUbuntu);
             }
         }
 
