diff --git a/test/Common/SerialConfiguration.cs b/test/Common/SerialConfiguration.cs
index acf22a5..b9eb64f 100644
--- a/test/Common/SerialConfiguration.cs
+++ b/test/Common/SerialConfiguration.cs
@@ -36,9 +36,7 @@ public static string SourcePort
             {
                 if (s_SourcePort is null) {
                     lock (m_SyncLock) {
-                        if (s_SourcePort is null) {
-                            s_SourcePort = AppSettings.Settings[OSPrefix + "SourcePort"].Value;
-                        }
+                        s_SourcePort ??= AppSettings.Settings[OSPrefix + "SourcePort"].Value;
                     }
                 }
                 return s_SourcePort;
@@ -51,9 +49,7 @@ public static string DestPort
             {
                 if (s_DestPort is null) {
                     lock (m_SyncLock) {
-                        if (s_DestPort is null) {
-                            s_DestPort = AppSettings.Settings[OSPrefix + "DestPort"].Value;
-                        }
+                        s_DestPort ??= AppSettings.Settings[OSPrefix + "DestPort"].Value;
                     }
                 }
                 return s_DestPort;
diff --git a/test/SerialPortStreamManualTest/GlobalSuppressions.cs b/test/SerialPortStreamManualTest/GlobalSuppressions.cs
index 72fd823..2cefe20 100644
--- a/test/SerialPortStreamManualTest/GlobalSuppressions.cs
+++ b/test/SerialPortStreamManualTest/GlobalSuppressions.cs
@@ -5,5 +5,4 @@
 
 using System.Diagnostics.CodeAnalysis;
 
-[assembly: SuppressMessage("Style", "IDE0074:Use compound assignment", Justification = ".NET Framework 4.0 compatibility")]
 [assembly: SuppressMessage("Style", "IDE0230:Use UTF-8 string literal", Justification = "Testing byte streams, not UTF8 strings")]
diff --git a/test/SerialPortStreamNativeTest/GlobalSuppressions.cs b/test/SerialPortStreamNativeTest/GlobalSuppressions.cs
index 36cbf91..47da094 100644
--- a/test/SerialPortStreamNativeTest/GlobalSuppressions.cs
+++ b/test/SerialPortStreamNativeTest/GlobalSuppressions.cs
@@ -7,5 +7,4 @@
 
 [assembly: SuppressMessage("Performance", "CA1835:Prefer the 'Memory'-based overloads for 'ReadAsync' and 'WriteAsync'", Justification = "Explicit testing of API")]
 [assembly: SuppressMessage("Style", "IDE0056:Use index operator", Justification = ".NET 4.0 Framework Compatibility")]
-[assembly: SuppressMessage("Style", "IDE0074:Use compound assignment", Justification = ".NET Framework 4.0 compatibility")]
 [assembly: SuppressMessage("Style", "IDE0230:Use UTF-8 string literal", Justification = "Testing byte streams, not UTF8 strings")]
diff --git a/test/SerialPortStreamTest/GlobalSuppressions.cs b/test/SerialPortStreamTest/GlobalSuppressions.cs
index 5c8005b..8f348cd 100644
--- a/test/SerialPortStreamTest/GlobalSuppressions.cs
+++ b/test/SerialPortStreamTest/GlobalSuppressions.cs
@@ -6,6 +6,5 @@
 using System.Diagnostics.CodeAnalysis;
 
 [assembly: SuppressMessage("Style", "IDE0056:Use index operator", Justification = ".NET Framework 4.0 compatibility")]
-[assembly: SuppressMessage("Style", "IDE0074:Use compound assignment", Justification = ".NET Framework 4.0 compatibility")]
 [assembly: SuppressMessage("Style", "IDE0230:Use UTF-8 string literal", Justification = "Testing byte streams, not UTF8 strings")]
 [assembly: SuppressMessage("Performance", "CA1835:Prefer the 'Memory'-based overloads for 'ReadAsync' and 'WriteAsync'", Justification = "Specific API Test")]