diff --git a/QuickFIXn/SessionSchedule.cs b/QuickFIXn/SessionSchedule.cs
index 1a0434da7..b869b63b6 100755
--- a/QuickFIXn/SessionSchedule.cs
+++ b/QuickFIXn/SessionSchedule.cs
@@ -14,7 +14,7 @@ public class SessionSchedule
         public DayOfWeek? EndDay { get; }
 
         private readonly bool _isWeekdaysSession;
-        private readonly HashSet<DayOfWeek> _weekdays;
+        private readonly HashSet<DayOfWeek> _weekdays = new();
 
         public bool NonStopSession { get; }
 
@@ -90,7 +90,7 @@ public DateTime NextEndTime(DateTime utc)
             if (NonStopSession)
                 throw new InvalidOperationException("NonStopSession is set; this statement should be unreachable");
 
-            TimeSpan vEndTime = EndTime ?? throw new QuickFix.ConfigError("EndTime is null");
+            TimeSpan vEndTime = EndTime ?? throw new ConfigError("EndTime is null");
 
             if (utc.Kind != DateTimeKind.Utc)
                 throw new ArgumentException("Only UTC time is supported", nameof(utc));
@@ -133,10 +133,10 @@ private bool CheckDay(DateTime dt)
             if (NonStopSession)
                 throw new InvalidOperationException("NonStopSession is set; this statement should be unreachable");
 
-            DayOfWeek vStartDay = StartDay ?? throw new QuickFix.ConfigError("StartDay is null");
-            DayOfWeek vEndDay = EndDay ?? throw new QuickFix.ConfigError("EndDay is null");
-            TimeSpan vStartTime = StartTime ?? throw new QuickFix.ConfigError("StartTime is null");
-            TimeSpan vEndTime = EndTime ?? throw new QuickFix.ConfigError("EndTime is null");
+            DayOfWeek vStartDay = StartDay ?? throw new ConfigError("StartDay is null");
+            DayOfWeek vEndDay = EndDay ?? throw new ConfigError("EndDay is null");
+            TimeSpan vStartTime = StartTime ?? throw new ConfigError("StartTime is null");
+            TimeSpan vEndTime = EndTime ?? throw new ConfigError("EndTime is null");
 
             if (vStartDay < vEndDay)
             {
@@ -177,8 +177,8 @@ private bool CheckTime(TimeSpan time)
             if (NonStopSession)
                 return true;
 
-            TimeSpan vStartTime = StartTime ?? throw new QuickFix.ConfigError("StartTime is null");
-            TimeSpan vEndTime = EndTime ?? throw new QuickFix.ConfigError("EndTime is null");
+            TimeSpan vStartTime = StartTime ?? throw new ConfigError("StartTime is null");
+            TimeSpan vEndTime = EndTime ?? throw new ConfigError("EndTime is null");
 
             if (vStartTime.CompareTo(vEndTime) < 0)
             {
@@ -195,8 +195,8 @@ private bool CheckWeekdays(DateTime dt)
             if (NonStopSession)
                 throw new InvalidOperationException("NonStopSession is set; this statement should be unreachable");
 
-            TimeSpan vStartTime = StartTime ?? throw new QuickFix.ConfigError("StartTime is null");
-            TimeSpan vEndTime = EndTime ?? throw new QuickFix.ConfigError("EndTime is null");
+            TimeSpan vStartTime = StartTime ?? throw new ConfigError("StartTime is null");
+            TimeSpan vEndTime = EndTime ?? throw new ConfigError("EndTime is null");
 
             TimeSpan tod = dt.TimeOfDay;
 
@@ -216,7 +216,7 @@ private bool CheckWeekdays(DateTime dt)
             return _weekdays.Contains(targetDay);
         }
 
-        private DayOfWeek PreviousDay(DayOfWeek d) {
+        private static DayOfWeek PreviousDay(DayOfWeek d) {
             return d == DayOfWeek.Sunday
                 ? DayOfWeek.Saturday
                 : d - 1;
@@ -252,10 +252,10 @@ public SessionSchedule(SettingsDictionary settings)
             }
 
             if (!settings.Has(SessionSettings.START_DAY) && settings.Has(SessionSettings.END_DAY))
-                throw new QuickFix.ConfigError("EndDay used without StartDay");
+                throw new ConfigError("EndDay used without StartDay");
 
             if (settings.Has(SessionSettings.START_DAY) && !settings.Has(SessionSettings.END_DAY))
-                throw new QuickFix.ConfigError("StartDay used without EndDay");
+                throw new ConfigError("StartDay used without EndDay");
 
             if (settings.Has(SessionSettings.START_DAY) && settings.Has(SessionSettings.END_DAY))
             {
diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index ba834e8eb..a50aedc02 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -60,7 +60,6 @@ What's New
      * Also refactor the heck out of DateTimeConverter & tests: many functions renamed/deprecated
 * #847 - remove setting MillisecondsInTimeStamp (gbirchmeier)
      * Use TimestampPrecision instead (same as QF/j)
-* #844 - implement "Weekdays" setting (MichalUssuri/gbirchmeier)
 
 **Non-breaking changes**
 * #400 - added DDTool, a C#-based codegen, and deleted Ruby-based generator (gbirchmeier)
@@ -83,6 +82,7 @@ What's New
       Programming Model (APM), in order to catch unobserved SocketExceptions (nmandzyk)
     * Cleanup/nullable-ize SocketInitiatorThread (gbirchmeier)
 * #839 - change ScreenLog to output FIX messages with "|" instead of non-visible SOH (gbirchmeier)
+* #844 - implement "Weekdays" setting (MichalUssuri/gbirchmeier)
 
 ### v1.11.2:
 * same as v1.11.1, but I fixed the readme in the pushed nuget packages
diff --git a/UnitTests/SettingsDictionaryTests.cs b/UnitTests/SettingsDictionaryTests.cs
index 776e9a57e..00b59c8c9 100755
--- a/UnitTests/SettingsDictionaryTests.cs
+++ b/UnitTests/SettingsDictionaryTests.cs
@@ -117,7 +117,7 @@ public void TestGetDay()
 
         d.SetString("DAY_X", "invalid");
         var ex = Assert.Throws(typeof(ArgumentException), delegate { d.GetDay("DAY_X"); });
-        StringAssert.Contains("Cannot recognize this day: 'invalid'", ex.Message);
+        StringAssert.Contains("Cannot recognize this day: 'invalid'", ex!.Message);
     }
 
     [Test]
@@ -130,7 +130,7 @@ public void TestSetDay() {
         Assert.That(d.GetString("DAY4"), Is.EqualTo("Thursday"));
 
         var ex = Assert.Throws(typeof(ArgumentException), delegate { d.SetDay("X", (DayOfWeek)9); });
-        StringAssert.Contains("Not a valid DayOfWeek value", ex.Message);
+        StringAssert.Contains("Not a valid DayOfWeek value", ex!.Message);
     }
 
     [Test]