diff --git a/test/CTS/AssessmentControllerTest.cs b/test/CTS/AssessmentControllerTest.cs
index 289fcd92f..1abb1215e 100644
--- a/test/CTS/AssessmentControllerTest.cs
+++ b/test/CTS/AssessmentControllerTest.cs
@@ -258,7 +258,7 @@ private static bool IsForbidResult<T>(ActionResult<T> a)
                 var forbidResult = a.Result as ForbidResult;
                 if (result != null)
                 {
-                    Assert.Equal((int)HttpStatusCode.Forbidden, result?.StatusCode);
+                    Assert.Equal((int)HttpStatusCode.Forbidden, result.StatusCode);
                 }
                 Assert.True(result != null || forbidResult != null);
 
diff --git a/test/RAPS/RoleTemplateSimplifiedTests.cs b/test/RAPS/RoleTemplateSimplifiedTests.cs
new file mode 100644
index 000000000..aad8a1061
--- /dev/null
+++ b/test/RAPS/RoleTemplateSimplifiedTests.cs
@@ -0,0 +1,59 @@
+using Viper.Areas.RAPS.Models;
+using Viper.Models.RAPS;
+
+namespace Viper.test.RAPS
+{
+    public class RoleTemplateSimplifiedTests
+    {
+        [Fact]
+        public void Constructor_MapsScalarsAndFlattensRoles()
+        {
+            // arrange
+            var rt = new RoleTemplate
+            {
+                RoleTemplateId = 42,
+                TemplateName = "Test Template",
+                Description = "Desc",
+                RoleTemplateRoles = new List<RoleTemplateRole>
+                {
+                    new() { Role = new TblRole { RoleId = 1, Role = "Alpha", DisplayName = "Alpha" } },
+                    new() { Role = new TblRole { RoleId = 2, Role = "Beta", DisplayName = "Beta" } }
+                }
+            };
+
+            // act
+            var dto = new RoleTemplateSimplified(rt);
+
+            // assert
+            Assert.Equal(42, dto.RoleTemplateId);
+            Assert.Equal("Test Template", dto.TemplateName);
+            Assert.Equal("Desc", dto.Description);
+            var roles = dto.Roles.ToList();
+            Assert.Equal(2, roles.Count);
+            Assert.Equal(1, roles[0].RoleId);
+            Assert.Equal("Alpha", roles[0].FriendlyName);
+            Assert.Equal(2, roles[1].RoleId);
+            Assert.Equal("Beta", roles[1].FriendlyName);
+        }
+
+        [Fact]
+        public void Constructor_EmptyRoles_ReturnsEmptyCollection()
+        {
+            // arrange
+            var rt = new RoleTemplate
+            {
+                RoleTemplateId = 7,
+                TemplateName = "No Roles",
+                Description = "",
+                RoleTemplateRoles = new List<RoleTemplateRole>()
+            };
+
+            // act
+            var dto = new RoleTemplateSimplified(rt);
+
+            // assert
+            Assert.Equal(7, dto.RoleTemplateId);
+            Assert.Empty(dto.Roles);
+        }
+    }
+}
diff --git a/web/Areas/CMS/Models/CMSFile.cs b/web/Areas/CMS/Models/CMSFile.cs
index 23b42e996..39eeb9d70 100644
--- a/web/Areas/CMS/Models/CMSFile.cs
+++ b/web/Areas/CMS/Models/CMSFile.cs
@@ -1,6 +1,6 @@
 namespace Viper.Areas.CMS.Models
 {
-    public partial class CMSFile : Viper.Models.VIPER.File
+    public sealed class CMSFile : Viper.Models.VIPER.File
     {
         public string FriendlyURL { get; set; }
 
diff --git a/web/Areas/CTS/Controllers/AssessmentController.cs b/web/Areas/CTS/Controllers/AssessmentController.cs
index 3d8f8a3dd..6bbc142d5 100644
--- a/web/Areas/CTS/Controllers/AssessmentController.cs
+++ b/web/Areas/CTS/Controllers/AssessmentController.cs
@@ -297,7 +297,7 @@ public async Task<ActionResult<CreateUpdateStudentEpa>> CreateStudentEpa(CreateU
                     .Include(p => p.StudentInfo)
                     .Where(p => p.PersonId == epaData.StudentId)
                     .FirstOrDefaultAsync();
-            if (student == null || student?.StudentInfo?.ClassLevel == null)
+            if (student == null || student.StudentInfo?.ClassLevel == null)
             {
                 return BadRequest("Student not found");
             }
diff --git a/web/Areas/CTS/Controllers/CompetencyController.cs b/web/Areas/CTS/Controllers/CompetencyController.cs
index 8c729ab04..057e79154 100644
--- a/web/Areas/CTS/Controllers/CompetencyController.cs
+++ b/web/Areas/CTS/Controllers/CompetencyController.cs
@@ -136,10 +136,6 @@ public async Task<ActionResult<CompetencyDto>> UpdateComptency(int competencyId,
                 return NotFound();
             }
 
-            if (competency.CompetencyId == null || competency.CompetencyId <= 0)
-            {
-                return BadRequest("CompetencyId is required.");
-            }
             if (competency.Name.Length < 2 || competency.Number.Length < 1)
             {
                 return BadRequest("Name and Number are required.");
diff --git a/web/Areas/CTS/Models/AuditRow.cs b/web/Areas/CTS/Models/AuditRow.cs
index 240f5da35..536a6ea37 100644
--- a/web/Areas/CTS/Models/AuditRow.cs
+++ b/web/Areas/CTS/Models/AuditRow.cs
@@ -22,10 +22,10 @@ public AuditRow(CtsAudit dbAudit)
             Timestamp = dbAudit.TimeStamp;
             ModifiedById = dbAudit.ModifiedBy;
             ModifiedByName = dbAudit.Modifier.LastName + ", " + dbAudit.Modifier.FirstName;
-            if (dbAudit?.Encounter?.Student != null)
+            if (dbAudit.Encounter?.Student != null)
             {
-                ModifiedPersonId = dbAudit.Encounter?.StudentUserId;
-                ModifiedPersonName = dbAudit.Encounter?.Student?.LastName + ", " + dbAudit.Encounter?.Student?.FirstName;
+                ModifiedPersonId = dbAudit.Encounter.StudentUserId;
+                ModifiedPersonName = dbAudit.Encounter.Student.LastName + ", " + dbAudit.Encounter.Student.FirstName;
             }
 
         }
diff --git a/web/Areas/Effort/Services/PercentRolloverService.cs b/web/Areas/Effort/Services/PercentRolloverService.cs
index 3fe56d08a..4e4ab1d79 100644
--- a/web/Areas/Effort/Services/PercentRolloverService.cs
+++ b/web/Areas/Effort/Services/PercentRolloverService.cs
@@ -30,6 +30,10 @@ public PercentRolloverService(
 
     public async Task<PercentRolloverPreviewDto> GetRolloverPreviewAsync(int year, CancellationToken ct = default)
     {
+        // Bound year for DateTime constructions below (year and year+1 must be valid years).
+        ArgumentOutOfRangeException.ThrowIfLessThan(year, 1);
+        ArgumentOutOfRangeException.ThrowIfGreaterThan(year, 9998);
+
         var result = new PercentRolloverPreviewDto();
 
         result.SourceAcademicYear = year;
@@ -42,7 +46,7 @@ public async Task<PercentRolloverPreviewDto> GetRolloverPreviewAsync(int year, C
         var july1Start = new DateTime(year, 7, 1, 0, 0, 0, DateTimeKind.Local);
         result.OldEndDate = june30Start;
         result.NewStartDate = july1Start;
-        result.NewEndDate = new DateTime(year + 1, 6, 30, 0, 0, 0, DateTimeKind.Local);
+        result.NewEndDate = june30Start.AddYears(1);
 
         // Find assignments ending on June 30 of source year (any time on that day)
         var assignments = await _context.Percentages
diff --git a/web/Areas/Effort/Services/PercentageService.cs b/web/Areas/Effort/Services/PercentageService.cs
index 0589961f9..3170820cf 100644
--- a/web/Areas/Effort/Services/PercentageService.cs
+++ b/web/Areas/Effort/Services/PercentageService.cs
@@ -306,7 +306,8 @@ public async Task<PercentageValidationResult> ValidatePercentageAsync(
             .Where(p => !string.Equals(p.PercentAssignType.Class, LeaveTypeClass, StringComparison.OrdinalIgnoreCase))
             .Sum(p => (decimal)EffortConstants.ToDisplayPercent(p.PercentageValue));
 
-        if (isNewActive && type != null && !string.Equals(type.Class, LeaveTypeClass, StringComparison.OrdinalIgnoreCase))
+        // type is guaranteed non-null here: early-return above when result.IsValid==false (set when type==null).
+        if (isNewActive && !string.Equals(type!.Class, LeaveTypeClass, StringComparison.OrdinalIgnoreCase))
         {
             var newTotal = activeNonLeaveTotal + Math.Round(request.PercentageValue, EffortConstants.PercentDisplayDecimals);
             if (newTotal > 100)
diff --git a/web/Areas/RAPS/Controllers/RAPSController.cs b/web/Areas/RAPS/Controllers/RAPSController.cs
index cf544e83e..6c1325644 100644
--- a/web/Areas/RAPS/Controllers/RAPSController.cs
+++ b/web/Areas/RAPS/Controllers/RAPSController.cs
@@ -48,14 +48,18 @@ public override async Task OnActionExecutionAsync(ActionExecutingContext context
             List<string>? path = HttpContext?.Request?.Path.ToString().Split("/").ToList();
             int? rapsIdx = path?.FindIndex(p => p.Equals("raps", StringComparison.OrdinalIgnoreCase));
             string instance = "VIPER";
-            if (rapsIdx != null && rapsIdx > -1 && path?.Count > rapsIdx + 1)
-            {
-                instance = path[(int)rapsIdx + 1];
-            }
             string page = "";
-            if (rapsIdx != null && rapsIdx > -1 && path?.Count > rapsIdx + 2)
+            // rapsIdx is non-null iff path is non-null (it's derived from path?.FindIndex).
+            if (rapsIdx is { } idx && idx > -1)
             {
-                page = path[(int)rapsIdx + 2];
+                if (path!.Count > idx + 1)
+                {
+                    instance = path[idx + 1];
+                }
+                if (path.Count > idx + 2)
+                {
+                    page = path[idx + 2];
+                }
             }
             ViewData["ViperLeftNav"] = await Nav(roleIdValid ? roleId : null,
                 permIdValid ? permissionId : null,
diff --git a/web/Areas/RAPS/Controllers/RoleTemplatesController.cs b/web/Areas/RAPS/Controllers/RoleTemplatesController.cs
index d6c57c7b3..cca4257a1 100644
--- a/web/Areas/RAPS/Controllers/RoleTemplatesController.cs
+++ b/web/Areas/RAPS/Controllers/RoleTemplatesController.cs
@@ -42,12 +42,9 @@ public async Task<ActionResult<IEnumerable<RoleTemplateSimplified>>> GetRoleTemp
                 .OrderBy(rt => rt.TemplateName)
                 .ToListAsync();
 
-            List<RoleTemplateSimplified> roleTemplates = new();
-            foreach (var rt in dbRoleTemplates)
-            {
-                roleTemplates.Add(new RoleTemplateSimplified(rt));
-            }
-            return roleTemplates;
+            return dbRoleTemplates
+                .Select(rt => new RoleTemplateSimplified(rt))
+                .ToList();
         }
 
         // GET: RoleTemplates/5
@@ -186,8 +183,8 @@ public async Task<ActionResult<RoleTemplateApplyPreview>> RoleTemplateApply(stri
 
             return new RoleTemplateApplyPreview()
             {
-                DisplayName = user?.DisplayFullName ?? "User not found",
-                MemberId = user?.MothraId ?? "",
+                DisplayName = user.DisplayFullName,
+                MemberId = user.MothraId,
                 Roles = rolesToApply
             };
         }
diff --git a/web/Areas/RAPS/Models/RoleTemplateSimplified.cs b/web/Areas/RAPS/Models/RoleTemplateSimplified.cs
index 72d6cc5a9..149ef9d13 100644
--- a/web/Areas/RAPS/Models/RoleTemplateSimplified.cs
+++ b/web/Areas/RAPS/Models/RoleTemplateSimplified.cs
@@ -11,7 +11,7 @@ public class RoleTemplateSimplified
 
         public string Description { get; set; } = null!;
 
-        public virtual ICollection<RoleSimplified> Roles { get; set; } = new List<RoleSimplified>();
+        public ICollection<RoleSimplified> Roles { get; set; } = new List<RoleSimplified>();
 
         public RoleTemplateSimplified() { }
         public RoleTemplateSimplified(RoleTemplate rt)
diff --git a/web/Areas/RAPS/Services/RAPSAuditService.cs b/web/Areas/RAPS/Services/RAPSAuditService.cs
index eda28d872..1dc25f41a 100644
--- a/web/Areas/RAPS/Services/RAPSAuditService.cs
+++ b/web/Areas/RAPS/Services/RAPSAuditService.cs
@@ -145,11 +145,11 @@ public async Task<List<AuditLog>> GetMemberRolesAndPermissionHistory(string inst
             Dictionary<string, List<string>> actionsPerformedOnObject = new();
             foreach (AuditLog auditLog in auditEntries)
             {
-                if (auditLog?.RoleId != null || auditLog?.PermissionId != null)
+                if (auditLog.RoleId != null || auditLog.PermissionId != null)
                 {
-                    string key = auditLog?.RoleId != null
+                    string key = auditLog.RoleId != null
                         ? "role-" + auditLog.RoleId
-                        : "permission-" + auditLog!.PermissionId;
+                        : "permission-" + auditLog.PermissionId;
                     if (actionsPerformedOnObject.ContainsKey(key))
                     {
                         List<string> moreRecentActions = actionsPerformedOnObject[key];
diff --git a/web/Classes/Utilities/AcademicYearHelper.cs b/web/Classes/Utilities/AcademicYearHelper.cs
index 921e298ac..321beeeff 100644
--- a/web/Classes/Utilities/AcademicYearHelper.cs
+++ b/web/Classes/Utilities/AcademicYearHelper.cs
@@ -52,8 +52,8 @@ public static List<int> GetTermCodesForAcademicYear(IEnumerable<int> allTermCode
     /// </summary>
     public static DateTime GetAcademicYearStart(DateTime date)
     {
-        var year = date.Month < 7 ? date.Year - 1 : date.Year;
-        return new DateTime(year, 7, 1, 0, 0, 0, DateTimeKind.Local);
+        var julyOfYear = new DateTime(date.Year, 7, 1, 0, 0, 0, DateTimeKind.Local);
+        return date.Month < 7 ? julyOfYear.AddYears(-1) : julyOfYear;
     }
 
     /// <summary>
diff --git a/web/Controllers/HomeController.cs b/web/Controllers/HomeController.cs
index d854ff6ed..d7af6b21d 100644
--- a/web/Controllers/HomeController.cs
+++ b/web/Controllers/HomeController.cs
@@ -147,7 +147,7 @@ public IActionResult EmulateUser(string loginId)
 
                 if (protector != null && emulatedUser.LoginId != null)
                 {
-                    string? encryptedEmulatedLoginId = protector?.Protect(emulatedUser.LoginId);
+                    string encryptedEmulatedLoginId = protector.Protect(emulatedUser.LoginId);
 
                     // set emulating cached item to expire after 30 minutes of inactivity
                     HttpHelper.Cache?.Set(ClaimsTransformer.EmulationCacheNamePrefix + trueLoginId, encryptedEmulatedLoginId, (new MemoryCacheEntryOptions().SetSlidingExpiration(TimeSpan.FromMinutes(30))));
@@ -319,7 +319,8 @@ private async Task<IActionResult> AuthenticateCasLogin(string? ticket, string? r
                 {
                     var claimsIdentity = new ClaimsIdentity(new[] { new Claim(ClaimTypes.Name, validatedUserName), new Claim(ClaimTypes.NameIdentifier, validatedUserName), new Claim(ClaimTypes.AuthenticationMethod, "CAS") }, CookieAuthenticationDefaults.AuthenticationScheme);
 
-                    XElement? attributesNode = successNode?.Element(_ns + "attributes");
+                    // successNode is guaranteed non-null here: validatedUserName is derived from successNode?.Element(user)?.Value.
+                    XElement? attributesNode = successNode!.Element(_ns + "attributes");
                     if (attributesNode != null)
                     {
                         foreach (string attributeName in _casAttributesToCapture)
diff --git a/web/Models/Students/StudentClassYear.cs b/web/Models/Students/StudentClassYear.cs
index 6c77638f2..71020ab09 100644
--- a/web/Models/Students/StudentClassYear.cs
+++ b/web/Models/Students/StudentClassYear.cs
@@ -3,7 +3,7 @@
 
 namespace Viper.Models.Students
 {
-    public class StudentClassYear
+    public sealed class StudentClassYear
     {
 
         public int StudentClassYearId { get; set; }
@@ -20,10 +20,10 @@ public class StudentClassYear
         public int? UpdatedBy { get; set; }
         public string? Comment { get; set; }
 
-        public virtual Person? Student { get; set; }
-        public virtual ClassYearLeftReason? ClassYearLeftReason { get; set; }
-        public virtual Person? AddedByPerson { get; set; }
-        public virtual Person? UpdatedByPerson { get; set; }
+        public Person? Student { get; set; }
+        public ClassYearLeftReason? ClassYearLeftReason { get; set; }
+        public Person? AddedByPerson { get; set; }
+        public Person? UpdatedByPerson { get; set; }
 
         [NotMapped]
         public string? LeftReasonText
diff --git a/web/Program.cs b/web/Program.cs
index 5fee3318b..49e95f988 100644
--- a/web/Program.cs
+++ b/web/Program.cs
@@ -11,6 +11,7 @@
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Caching.Memory;
 using Microsoft.Extensions.FileProviders;
+using System.Reflection;
 using System.Text.Json.Serialization;
 using NLog;
 using NLog.Web;
@@ -542,26 +543,29 @@ void SetAwsCredentials(Logger logger)
 {
     XElement xAwsCredentials = XElement.Load(awsCredentialsFilePath, LoadOptions.None);
 
-    if (!String.IsNullOrWhiteSpace(xAwsCredentials?.Element("AccessKeyId")?.Value) && !String.IsNullOrWhiteSpace(xAwsCredentials?.Element("SecretAccessKey")?.Value))
+    var accessKey = xAwsCredentials.Element("AccessKeyId")?.Value;
+    var secretKey = xAwsCredentials.Element("SecretAccessKey")?.Value;
+    if (!String.IsNullOrWhiteSpace(accessKey) && !String.IsNullOrWhiteSpace(secretKey))
     {
         // grab the credentials ouf of the xml file to stor in the encrypted json file inthe profile
         var options = new CredentialProfileOptions
         {
-            AccessKey = xAwsCredentials?.Element("AccessKeyId")?.Value.Trim(),
-            SecretKey = xAwsCredentials?.Element("SecretAccessKey")?.Value.Trim()
+            AccessKey = accessKey.Trim(),
+            SecretKey = secretKey.Trim()
         };
 
         var profile = new CredentialProfile("default", options);
         // if a region was specified in the xml then use the specified region else default to USWest1
-        if (!string.IsNullOrWhiteSpace(xAwsCredentials?.Element("RegionEndpoint")?.Value) && xAwsCredentials?.Element("RegionEndpoint") != null)
+        var regionValue = xAwsCredentials.Element("RegionEndpoint")?.Value.Trim();
+        if (!string.IsNullOrWhiteSpace(regionValue))
         {
-#pragma warning disable CS8604 // Possible null reference argument.
-            profile.Region = typeof(Amazon.RegionEndpoint).GetField(xAwsCredentials?.Element("RegionEndpoint")?.Value)?.GetValue(null) as Amazon.RegionEndpoint;
-#pragma warning restore CS8604 // Possible null reference argument.
+            const BindingFlags regionFieldFlags = BindingFlags.Public | BindingFlags.Static | BindingFlags.IgnoreCase;
+            profile.Region = typeof(RegionEndpoint).GetField(regionValue, regionFieldFlags)?.GetValue(null) as RegionEndpoint
+                ?? RegionEndpoint.USWest1;
         }
         else
         {
-            profile.Region = Amazon.RegionEndpoint.USWest1;
+            profile.Region = RegionEndpoint.USWest1;
         }
         var netSDKFile = new NetSDKCredentialsFile();
         netSDKFile.RegisterProfile(profile);