diff --git a/apps/judicial-system/backend/src/app/modules/case/case.service.ts b/apps/judicial-system/backend/src/app/modules/case/case.service.ts
index ddd76c7772d4..5c9f66ea866d 100644
--- a/apps/judicial-system/backend/src/app/modules/case/case.service.ts
+++ b/apps/judicial-system/backend/src/app/modules/case/case.service.ts
@@ -20,7 +20,7 @@ import type { Logger } from '@island.is/logging'
 import { LOGGER_PROVIDER } from '@island.is/logging'
 import { type ConfigType } from '@island.is/nest/config'
 
-import { formatNationalId } from '@island.is/judicial-system/formatters'
+import { normalizeAndFormatNationalId } from '@island.is/judicial-system/formatters'
 import {
   Message,
   MessageService,
@@ -1355,42 +1355,46 @@ export class CaseService {
     caseId: string,
     defendant: Defendant,
   ): Promise<Case[]> {
-    let whereClause: WhereOptions = {
-      type: CaseType.INDICTMENT,
-      id: { [Op.ne]: caseId },
-      state: [CaseState.RECEIVED],
-    }
+    const whereClause: WhereOptions = [
+      { isArchived: false },
+      { type: CaseType.INDICTMENT },
+      { id: { [Op.ne]: caseId } },
+      { state: CaseState.RECEIVED },
+    ]
 
     if (defendant.noNationalId) {
-      whereClause = {
-        ...whereClause,
-        [Op.and]: [
-          { '$defendants.national_id$': defendant.nationalId },
-          { '$defendants.name$': defendant.name },
-        ],
-      }
+      whereClause.push({
+        id: {
+          [Op.in]: Sequelize.literal(`
+            (SELECT case_id
+              FROM defendant
+              WHERE national_id = '${defendant.nationalId}'
+              AND name = '${defendant.name}'
+          )`),
+        },
+      })
     } else {
-      const formattedNationalId = formatNationalId(defendant.nationalId)
-      whereClause = {
-        ...whereClause,
-        [Op.or]: [
-          { '$defendants.national_id$': defendant.nationalId },
-          { '$defendants.national_id$': formattedNationalId },
-        ],
-      }
+      const [normalizedNationalId, formattedNationalId] =
+        normalizeAndFormatNationalId(defendant.nationalId)
+
+      whereClause.push({
+        id: {
+          [Op.in]: Sequelize.literal(`
+            (SELECT case_id
+              FROM defendant
+              WHERE national_id in ('${normalizedNationalId}', '${formattedNationalId}')
+          )`),
+        },
+      })
     }
 
     return this.caseModel.findAll({
       include: [
+        { model: Institution, as: 'court' },
         { model: Defendant, as: 'defendants' },
-        {
-          model: DateLog,
-          as: 'dateLogs',
-        },
       ],
-      order: [[{ model: DateLog, as: 'dateLogs' }, 'created', 'DESC']],
       attributes: ['id', 'courtCaseNumber', 'type', 'state'],
-      where: whereClause,
+      where: { [Op.and]: whereClause },
     })
   }
 
diff --git a/apps/judicial-system/backend/src/app/modules/case/filters/case.filter.ts b/apps/judicial-system/backend/src/app/modules/case/filters/case.filter.ts
index 64c00f550136..dfb9f7bc678f 100644
--- a/apps/judicial-system/backend/src/app/modules/case/filters/case.filter.ts
+++ b/apps/judicial-system/backend/src/app/modules/case/filters/case.filter.ts
@@ -1,4 +1,4 @@
-import { formatNationalId } from '@island.is/judicial-system/formatters'
+import { normalizeAndFormatNationalId } from '@island.is/judicial-system/formatters'
 import type { User } from '@island.is/judicial-system/types'
 import {
   CaseAppealState,
@@ -330,22 +330,27 @@ const canDefenceUserAccessCase = (theCase: Case, user: User): boolean => {
     }
   }
 
-  const formattedNationalId = formatNationalId(user.nationalId)
+  const normalizedAndFormattedNationalId = normalizeAndFormatNationalId(
+    user.nationalId,
+  )
+
   // Check case defender access
   if (isIndictmentCase(theCase.type)) {
     if (
       !theCase.defendants?.some(
         (defendant) =>
-          defendant.defenderNationalId === user.nationalId ||
-          defendant.defenderNationalId === formattedNationalId,
+          defendant.defenderNationalId &&
+          normalizedAndFormattedNationalId.includes(
+            defendant.defenderNationalId,
+          ),
       )
     ) {
       return false
     }
   } else {
     if (
-      theCase.defenderNationalId !== user.nationalId &&
-      theCase.defenderNationalId !== formattedNationalId
+      !theCase.defenderNationalId ||
+      !normalizedAndFormattedNationalId.includes(theCase.defenderNationalId)
     ) {
       return false
     }
diff --git a/apps/judicial-system/backend/src/app/modules/case/filters/cases.filter.ts b/apps/judicial-system/backend/src/app/modules/case/filters/cases.filter.ts
index c9fa79cc834b..0ccb2aa3c953 100644
--- a/apps/judicial-system/backend/src/app/modules/case/filters/cases.filter.ts
+++ b/apps/judicial-system/backend/src/app/modules/case/filters/cases.filter.ts
@@ -2,7 +2,7 @@ import { Op, Sequelize, WhereOptions } from 'sequelize'
 
 import { ForbiddenException } from '@nestjs/common'
 
-import { formatNationalId } from '@island.is/judicial-system/formatters'
+import { normalizeAndFormatNationalId } from '@island.is/judicial-system/formatters'
 import type { User } from '@island.is/judicial-system/types'
 import {
   CaseAppealState,
@@ -216,7 +216,9 @@ const getPrisonAdminUserCasesQueryFilter = (): WhereOptions => {
 }
 
 const getDefenceUserCasesQueryFilter = (user: User): WhereOptions => {
-  const formattedNationalId = formatNationalId(user.nationalId)
+  const [normalizedNationalId, formattedNationalId] =
+    normalizeAndFormatNationalId(user.nationalId)
+
   const options: WhereOptions = [
     { is_archived: false },
     {
@@ -238,6 +240,8 @@ const getDefenceUserCasesQueryFilter = (user: User): WhereOptions => {
                 {
                   [Op.and]: [
                     { state: CaseState.RECEIVED },
+                    // The following condition will filter out all date logs that are not of type ARRAIGNMENT_DATE
+                    // but that should be ok for request cases since they only have one date log
                     { '$dateLogs.date_type$': DateType.ARRAIGNMENT_DATE },
                   ],
                 },
@@ -251,7 +255,7 @@ const getDefenceUserCasesQueryFilter = (user: User): WhereOptions => {
               ],
             },
             {
-              defender_national_id: [user.nationalId, formattedNationalId],
+              defender_national_id: [normalizedNationalId, formattedNationalId],
             },
           ],
         },
@@ -266,10 +270,13 @@ const getDefenceUserCasesQueryFilter = (user: User): WhereOptions => {
               ],
             },
             {
-              '$defendants.defender_national_id$': [
-                user.nationalId,
-                formattedNationalId,
-              ],
+              id: {
+                [Op.in]: Sequelize.literal(`
+                (SELECT case_id
+                  FROM defendant
+                  WHERE defender_national_id in ('${normalizedNationalId}', '${formattedNationalId}'))
+              `),
+              },
             },
           ],
         },
diff --git a/apps/judicial-system/backend/src/app/modules/case/filters/test/cases.filter.spec.ts b/apps/judicial-system/backend/src/app/modules/case/filters/test/cases.filter.spec.ts
index 1c412b863bd7..0e2217081425 100644
--- a/apps/judicial-system/backend/src/app/modules/case/filters/test/cases.filter.spec.ts
+++ b/apps/judicial-system/backend/src/app/modules/case/filters/test/cases.filter.spec.ts
@@ -452,10 +452,13 @@ describe('getCasesQueryFilter', () => {
                   ],
                 },
                 {
-                  '$defendants.defender_national_id$': [
-                    user.nationalId,
-                    user.nationalId,
-                  ],
+                  id: {
+                    [Op.in]: Sequelize.literal(`
+                (SELECT case_id
+                  FROM defendant
+                  WHERE defender_national_id in ('${user.nationalId}', '${user.nationalId}'))
+              `),
+                  },
                 },
               ],
             },
diff --git a/apps/judicial-system/backend/src/app/modules/case/internalCase.service.ts b/apps/judicial-system/backend/src/app/modules/case/internalCase.service.ts
index 741699620065..ae2fb90f556e 100644
--- a/apps/judicial-system/backend/src/app/modules/case/internalCase.service.ts
+++ b/apps/judicial-system/backend/src/app/modules/case/internalCase.service.ts
@@ -20,7 +20,7 @@ import type { ConfigType } from '@island.is/nest/config'
 
 import {
   formatCaseType,
-  formatNationalId,
+  normalizeAndFormatNationalId,
 } from '@island.is/judicial-system/formatters'
 import {
   CaseFileCategory,
@@ -1202,8 +1202,6 @@ export class InternalCaseService {
   // As this is only currently used by the digital mailbox API
   // we will only return indictment cases that have a court date
   async getIndictmentCases(nationalId: string): Promise<Case[]> {
-    const formattedNationalId = formatNationalId(nationalId)
-
     return this.caseModel.findAll({
       include: [
         { model: Defendant, as: 'defendants' },
@@ -1220,19 +1218,14 @@ export class InternalCaseService {
       attributes: ['id', 'courtCaseNumber', 'type', 'state'],
       where: {
         type: CaseType.INDICTMENT,
-        [Op.or]: [
-          { '$defendants.national_id$': nationalId },
-          { '$defendants.national_id$': formattedNationalId },
-        ],
+        // The national id could be without a hyphen or with a hyphen so we need to
+        // search for both
+        '$defendants.national_id$': normalizeAndFormatNationalId(nationalId),
       },
     })
   }
 
   async getIndictmentCase(caseId: string, nationalId: string): Promise<Case> {
-    // The national id could be without a hyphen or with a hyphen so we need to
-    // search for both
-    const formattedNationalId = formatNationalId(nationalId)
-
     const caseById = await this.caseModel.findOne({
       include: [
         { model: Defendant, as: 'defendants' },
@@ -1246,10 +1239,9 @@ export class InternalCaseService {
       where: {
         type: CaseType.INDICTMENT,
         id: caseId,
-        [Op.or]: [
-          { '$defendants.national_id$': nationalId },
-          { '$defendants.national_id$': formattedNationalId },
-        ],
+        // The national id could be without a hyphen or with a hyphen so we need to
+        // search for both
+        '$defendants.national_id$': normalizeAndFormatNationalId(nationalId),
       },
     })
 
diff --git a/apps/judicial-system/backend/src/app/modules/case/limitedAccessCase.service.ts b/apps/judicial-system/backend/src/app/modules/case/limitedAccessCase.service.ts
index aa51cb9a6cda..1f9b75a06b9f 100644
--- a/apps/judicial-system/backend/src/app/modules/case/limitedAccessCase.service.ts
+++ b/apps/judicial-system/backend/src/app/modules/case/limitedAccessCase.service.ts
@@ -13,7 +13,7 @@ import { InjectModel } from '@nestjs/sequelize'
 import type { Logger } from '@island.is/logging'
 import { LOGGER_PROVIDER } from '@island.is/logging'
 
-import { formatNationalId } from '@island.is/judicial-system/formatters'
+import { normalizeAndFormatNationalId } from '@island.is/judicial-system/formatters'
 import { MessageService, MessageType } from '@island.is/judicial-system/message'
 import type { User as TUser } from '@island.is/judicial-system/types'
 import {
@@ -363,14 +363,10 @@ export class LimitedAccessCaseService {
   }
 
   async findDefenderByNationalId(nationalId: string): Promise<User> {
-    const formattedNationalId = formatNationalId(nationalId)
     return this.caseModel
       .findOne({
         where: {
-          [Op.or]: [
-            { defenderNationalId: formattedNationalId },
-            { defenderNationalId: nationalId },
-          ],
+          defenderNationalId: normalizeAndFormatNationalId(nationalId),
           state: { [Op.not]: CaseState.DELETED },
           isArchived: false,
         },
diff --git a/apps/judicial-system/backend/src/app/modules/case/test/limitedAccessCaseController/findDefenderByNationalId.spec.ts b/apps/judicial-system/backend/src/app/modules/case/test/limitedAccessCaseController/findDefenderByNationalId.spec.ts
index 7979e7477454..d2fb64ec33ff 100644
--- a/apps/judicial-system/backend/src/app/modules/case/test/limitedAccessCaseController/findDefenderByNationalId.spec.ts
+++ b/apps/judicial-system/backend/src/app/modules/case/test/limitedAccessCaseController/findDefenderByNationalId.spec.ts
@@ -75,10 +75,7 @@ describe('LimitedAccessCaseController - Find defender by national id', () => {
     it('should look for defender', () => {
       expect(mockCaseModel.findOne).toHaveBeenCalledWith({
         where: {
-          [Op.or]: [
-            { defenderNationalId: formattedDefenderNationalId },
-            { defenderNationalId: defenderNationalId },
-          ],
+          defenderNationalId: [defenderNationalId, formattedDefenderNationalId],
           state: { [Op.not]: CaseState.DELETED },
           isArchived: false,
         },
diff --git a/apps/judicial-system/backend/src/app/modules/defendant/defendant.service.ts b/apps/judicial-system/backend/src/app/modules/defendant/defendant.service.ts
index aa71527fd435..f323632f2476 100644
--- a/apps/judicial-system/backend/src/app/modules/defendant/defendant.service.ts
+++ b/apps/judicial-system/backend/src/app/modules/defendant/defendant.service.ts
@@ -11,7 +11,7 @@ import { InjectModel } from '@nestjs/sequelize'
 import type { Logger } from '@island.is/logging'
 import { LOGGER_PROVIDER } from '@island.is/logging'
 
-import { formatNationalId } from '@island.is/judicial-system/formatters'
+import { normalizeAndFormatNationalId } from '@island.is/judicial-system/formatters'
 import {
   Message,
   MessageService,
@@ -201,17 +201,12 @@ export class DefendantService {
     defendantNationalId: string,
     update: UpdateDefendantDto,
   ): Promise<Defendant> {
-    const formattedNationalId = formatNationalId(defendantNationalId)
-
     const [numberOfAffectedRows, defendants] = await this.defendantModel.update(
       update,
       {
         where: {
           caseId,
-          [Op.or]: [
-            { national_id: formattedNationalId },
-            { national_id: defendantNationalId },
-          ],
+          national_id: normalizeAndFormatNationalId(defendantNationalId),
         },
         returning: true,
       },
diff --git a/apps/judicial-system/digital-mailbox-api/src/app/modules/cases/models/subpoena.response.ts b/apps/judicial-system/digital-mailbox-api/src/app/modules/cases/models/subpoena.response.ts
index a39933df0f9f..ffbacab59c49 100644
--- a/apps/judicial-system/digital-mailbox-api/src/app/modules/cases/models/subpoena.response.ts
+++ b/apps/judicial-system/digital-mailbox-api/src/app/modules/cases/models/subpoena.response.ts
@@ -4,7 +4,7 @@ import { ApiProperty } from '@nestjs/swagger'
 
 import {
   formatDate,
-  formatNationalId,
+  normalizeAndFormatNationalId,
 } from '@island.is/judicial-system/formatters'
 import { DateType, DefenderChoice } from '@island.is/judicial-system/types'
 
@@ -47,13 +47,14 @@ export class SubpoenaResponse {
     defendantNationalId: string,
     lang?: string,
   ): SubpoenaResponse {
-    const formattedNationalId = formatNationalId(defendantNationalId)
     const t = getTranslations(lang)
 
     const defendantInfo = internalCase.defendants.find(
       (defendant) =>
-        defendant.nationalId === formattedNationalId ||
-        defendant.nationalId === defendantNationalId,
+        defendant.nationalId &&
+        normalizeAndFormatNationalId(defendantNationalId).includes(
+          defendant.nationalId,
+        ),
     )
 
     const waivedRight = defendantInfo?.defenderChoice === DefenderChoice.WAIVE
diff --git a/apps/judicial-system/web/src/components/CourtArrangements/CourtArrangements.tsx b/apps/judicial-system/web/src/components/CourtArrangements/CourtArrangements.tsx
index 2e02d96fbad2..9e8ee4794428 100644
--- a/apps/judicial-system/web/src/components/CourtArrangements/CourtArrangements.tsx
+++ b/apps/judicial-system/web/src/components/CourtArrangements/CourtArrangements.tsx
@@ -81,7 +81,7 @@ export const useCourtArrangements = (
 
     setCourtDate((previous) => ({
       ...previous,
-      date: date ? formatDateForServer(date) : null,
+      date: date ? date.toISOString() : null,
     }))
   }
 
diff --git a/apps/judicial-system/web/src/routes/Court/Indictments/Conclusion/SelectConnectedCase.tsx b/apps/judicial-system/web/src/routes/Court/Indictments/Conclusion/SelectConnectedCase.tsx
index 40f108d5d000..8c09daeb2ccd 100644
--- a/apps/judicial-system/web/src/routes/Court/Indictments/Conclusion/SelectConnectedCase.tsx
+++ b/apps/judicial-system/web/src/routes/Court/Indictments/Conclusion/SelectConnectedCase.tsx
@@ -41,10 +41,18 @@ const SelectConnectedCase: FC<Props> = ({ workingCase, setWorkingCase }) => {
     }))
   }
 
-  const connectedCases = connectedCasesData?.connectedCases?.map((aCase) => ({
-    label: `${aCase.courtCaseNumber}`,
-    value: aCase.id,
-  })) as ConnectedCaseOption[]
+  const connectedCases = connectedCasesData?.connectedCases
+    ?.filter(
+      // The filtering is done here rather than on the server side
+      // as we may allow more relaxed merging later on
+      (connectedCase) =>
+        connectedCase.defendants?.length === 1 &&
+        connectedCase.court?.id === workingCase.court?.id,
+    )
+    ?.map((connectedCase) => ({
+      label: `${connectedCase.courtCaseNumber}`,
+      value: connectedCase.id,
+    })) as ConnectedCaseOption[]
 
   // For now we only want to allow cases with a single defendant to be able to merge
   // in to another case
diff --git a/libs/judicial-system/formatters/src/lib/formatters.spec.ts b/libs/judicial-system/formatters/src/lib/formatters.spec.ts
index a97d6ea41e74..45e9a52f7cc9 100644
--- a/libs/judicial-system/formatters/src/lib/formatters.spec.ts
+++ b/libs/judicial-system/formatters/src/lib/formatters.spec.ts
@@ -16,6 +16,7 @@ import {
   formatNationalId,
   formatPhoneNumber,
   indictmentSubtypes,
+  normalizeAndFormatNationalId,
   readableIndictmentSubtypes,
   sanitize,
   splitStringByComma,
@@ -219,6 +220,30 @@ describe('formatNationalId', () => {
   })
 })
 
+describe('normalizeAndFormatNationalId', () => {
+  test('should format national id with dash', () => {
+    // Arrange
+    const nationalId = '123456-7890'
+
+    // Act
+    const res = normalizeAndFormatNationalId(nationalId)
+
+    // Assert
+    expect(res).toEqual(['1234567890', '123456-7890'])
+  })
+
+  test('should format national id without dash', () => {
+    // Arrange
+    const nationalId = '1234567890'
+
+    // Act
+    const res = normalizeAndFormatNationalId(nationalId)
+
+    // Assert
+    expect(res).toEqual(['1234567890', '123456-7890'])
+  })
+})
+
 describe('formatDOB', () => {
   it('should format a national id string for a valid national id', () => {
     // Arrange
diff --git a/libs/judicial-system/formatters/src/lib/formatters.ts b/libs/judicial-system/formatters/src/lib/formatters.ts
index a25433fc0ffd..c54b451091f1 100644
--- a/libs/judicial-system/formatters/src/lib/formatters.ts
+++ b/libs/judicial-system/formatters/src/lib/formatters.ts
@@ -76,6 +76,12 @@ export const formatNationalId = (nationalId?: string | null): string => {
   }
 }
 
+export const normalizeAndFormatNationalId = (
+  nationalId?: string | null,
+): [string, string] => {
+  return [nationalId?.replace(/-/g, '') ?? '', formatNationalId(nationalId)]
+}
+
 export const getInitials = (name?: string | null): string | undefined => {
   if (!name?.trim()) return undefined