diff --git a/lib/permissions/minimally-encoded-raw-thread-info-validators.js b/lib/permissions/minimally-encoded-raw-thread-info-validators.js
--- a/lib/permissions/minimally-encoded-raw-thread-info-validators.js
+++ b/lib/permissions/minimally-encoded-raw-thread-info-validators.js
@@ -11,6 +11,7 @@
   MemberInfoWithPermissions,
   ThreadCurrentUserInfo,
   ThinRawThreadInfo,
+  ThickRawThreadInfo,
   RoleInfo,
   RoleInfoWithoutSpecialRole,
   ThinRawThreadInfoWithoutSpecialRole,
@@ -20,9 +21,12 @@
 import { threadSubscriptionValidator } from '../types/subscription-types.js';
 import {
   type LegacyThinRawThreadInfo,
+  type LegacyRawThreadInfo,
   legacyMemberInfoValidator,
   legacyThinRawThreadInfoValidator,
   legacyThreadCurrentUserInfoValidator,
+  legacyThickRawThreadInfoValidator,
+  legacyThreadInfoValidator,
 } from '../types/thread-types.js';
 import { tBool, tID, tShape, tUserID } from '../utils/validation-utils.js';
 
@@ -102,6 +106,15 @@
     currentUser: threadCurrentUserInfoValidator,
   });
 
+const thickRawThreadInfoValidator: TInterface<ThickRawThreadInfo> =
+  tShape<ThickRawThreadInfo>({
+    ...legacyThickRawThreadInfoValidator.meta.props,
+    minimallyEncoded: tBool(true),
+    members: t.list(minimallyEncodedThickMemberInfoValidator),
+    roles: t.dict(tID, roleInfoValidator),
+    currentUser: threadCurrentUserInfoValidator,
+  });
+
 const roleInfoWithoutSpecialRolesValidator: TInterface<RoleInfoWithoutSpecialRole> =
   tShape<RoleInfoWithoutSpecialRole>({
     ...roleInfoValidatorBase,
@@ -124,6 +137,17 @@
   thinRawThreadInfoWithoutSpecialRolesValidator,
 ]);
 
+const rawThreadInfoValidator: TUnion<ThinRawThreadInfo | ThickRawThreadInfo> =
+  t.union([thinRawThreadInfoValidator, thickRawThreadInfoValidator]);
+
+const mixedThreadInfoValidator: TUnion<
+  LegacyRawThreadInfo | ThinRawThreadInfo | ThickRawThreadInfo,
+> = t.union([
+  legacyThreadInfoValidator,
+  thinRawThreadInfoValidator,
+  thickRawThreadInfoValidator,
+]);
+
 export {
   memberInfoWithPermissionsValidator,
   memberInfoSansPermissionsValidator,
@@ -133,4 +157,6 @@
   threadCurrentUserInfoValidator,
   thinRawThreadInfoValidator,
   mixedThinRawThreadInfoValidator,
+  mixedThreadInfoValidator,
+  rawThreadInfoValidator,
 };
diff --git a/lib/shared/updates/join-thread-spec.js b/lib/shared/updates/join-thread-spec.js
--- a/lib/shared/updates/join-thread-spec.js
+++ b/lib/shared/updates/join-thread-spec.js
@@ -6,7 +6,7 @@
 
 import type { UpdateInfoFromRawInfoParams, UpdateSpec } from './update-spec.js';
 import { createReplaceThreadOperation } from '../../ops/create-replace-thread-operation.js';
-import { mixedThinRawThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
+import { mixedThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
 import {
   type RawEntryInfo,
   rawEntryInfoValidator,
@@ -168,7 +168,7 @@
     type: tNumber(updateTypes.JOIN_THREAD),
     id: t.String,
     time: t.Number,
-    threadInfo: mixedThinRawThreadInfoValidator,
+    threadInfo: mixedThreadInfoValidator,
     rawMessageInfos: t.list(rawMessageInfoValidator),
     truncationStatus: messageTruncationStatusValidator,
     rawEntryInfos: t.list(rawEntryInfoValidator),
diff --git a/lib/shared/updates/update-thread-spec.js b/lib/shared/updates/update-thread-spec.js
--- a/lib/shared/updates/update-thread-spec.js
+++ b/lib/shared/updates/update-thread-spec.js
@@ -6,7 +6,7 @@
 
 import type { UpdateInfoFromRawInfoParams, UpdateSpec } from './update-spec.js';
 import { createReplaceThreadOperation } from '../../ops/create-replace-thread-operation.js';
-import { mixedThinRawThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
+import { mixedThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
 import type { RawThreadInfos } from '../../types/thread-types.js';
 import { updateTypes } from '../../types/update-types-enum.js';
 import type {
@@ -112,7 +112,7 @@
     type: tNumber(updateTypes.UPDATE_THREAD),
     id: t.String,
     time: t.Number,
-    threadInfo: mixedThinRawThreadInfoValidator,
+    threadInfo: mixedThreadInfoValidator,
   }),
   getUpdatedThreadInfo(update: ThreadUpdateInfo) {
     return update.threadInfo;
diff --git a/lib/types/request-types.js b/lib/types/request-types.js
--- a/lib/types/request-types.js
+++ b/lib/types/request-types.js
@@ -26,13 +26,14 @@
   entryInconsistencyReportValidatorShape,
 } from './report-types.js';
 import type { LegacyRawThreadInfo } from './thread-types.js';
+import { legacyThreadInfoValidator } from './thread-types.js';
 import {
   type CurrentUserInfo,
   currentUserInfoValidator,
   type AccountUserInfo,
   accountUserInfoValidator,
 } from './user-types.js';
-import { mixedThinRawThreadInfoValidator } from '../permissions/minimally-encoded-raw-thread-info-validators.js';
+import { rawThreadInfoValidator } from '../permissions/minimally-encoded-raw-thread-info-validators.js';
 import {
   tNumber,
   tShape,
@@ -164,7 +165,12 @@
     ),
     stateChanges: t.maybe(
       tShape<StateChanges>({
-        rawThreadInfos: t.maybe(t.list(mixedThinRawThreadInfoValidator)),
+        rawThreadInfos: t.maybe(
+          t.union([
+            t.list(legacyThreadInfoValidator),
+            t.list(rawThreadInfoValidator),
+          ]),
+        ),
         rawEntryInfos: t.maybe(t.list(rawEntryInfoValidator)),
         currentUserInfo: t.maybe(currentUserInfoValidator),
         userInfos: t.maybe(t.list(accountUserInfoValidator)),
diff --git a/lib/types/socket-types.js b/lib/types/socket-types.js
--- a/lib/types/socket-types.js
+++ b/lib/types/socket-types.js
@@ -54,7 +54,7 @@
   type LoggedOutUserInfo,
   loggedOutUserInfoValidator,
 } from './user-types.js';
-import { mixedThinRawThreadInfoValidator } from '../permissions/minimally-encoded-raw-thread-info-validators.js';
+import { mixedThreadInfoValidator } from '../permissions/minimally-encoded-raw-thread-info-validators.js';
 import { values } from '../utils/objects.js';
 import { tShape, tNumber, tID } from '../utils/validation-utils.js';
 
@@ -224,7 +224,7 @@
 }>;
 const serverFullStateSyncValidator = tShape<ServerFullStateSync>({
   ...baseFullStateSyncValidator.meta.props,
-  threadInfos: t.dict(tID, mixedThinRawThreadInfoValidator),
+  threadInfos: t.dict(tID, mixedThreadInfoValidator),
   currentUserInfo: currentUserInfoValidator,
 });
 
diff --git a/lib/types/thread-types.js b/lib/types/thread-types.js
--- a/lib/types/thread-types.js
+++ b/lib/types/thread-types.js
@@ -1,6 +1,6 @@
 // @flow
 
-import t, { type TInterface } from 'tcomb';
+import t, { type TInterface, type TUnion } from 'tcomb';
 
 import {
   type AvatarDBContent,
@@ -35,12 +35,13 @@
   type ThinThreadType,
   type ThickThreadType,
   thinThreadTypeValidator,
+  thickThreadTypeValidator,
 } from './thread-types-enum.js';
 import type { ClientUpdateInfo, ServerUpdateInfo } from './update-types.js';
 import type { UserInfo, UserInfos } from './user-types.js';
 import type { SpecialRole } from '../permissions/special-roles.js';
 import { type ThreadEntity } from '../utils/entity-text.js';
-import { tID, tShape, tUserID } from '../utils/validation-utils.js';
+import { tID, tShape, tUserID, tBool } from '../utils/validation-utils.js';
 
 export type LegacyMemberInfo = {
   +id: string,
@@ -200,6 +201,43 @@
     pinnedCount: t.maybe(t.Number),
   });
 
+export const thickMemberInfoValidator: TInterface<ThickMemberInfo> =
+  tShape<ThickMemberInfo>({
+    id: tUserID,
+    role: t.maybe(tID),
+    permissions: threadPermissionsInfoValidator,
+    subscription: threadSubscriptionValidator,
+    isSender: t.Boolean,
+  });
+
+export const legacyThickRawThreadInfoValidator: TInterface<LegacyThickRawThreadInfo> =
+  tShape<LegacyThickRawThreadInfo>({
+    thick: tBool(true),
+    id: tID,
+    type: thickThreadTypeValidator,
+    name: t.maybe(t.String),
+    avatar: t.maybe(clientAvatarValidator),
+    description: t.maybe(t.String),
+    color: t.String,
+    creationTime: t.Number,
+    parentThreadID: t.maybe(tID),
+    containingThreadID: t.maybe(tID),
+    members: t.list(thickMemberInfoValidator),
+    roles: t.dict(tID, clientLegacyRoleInfoValidator),
+    currentUser: legacyThreadCurrentUserInfoValidator,
+    sourceMessageID: t.maybe(tID),
+    repliesCount: t.Number,
+    pinnedCount: t.maybe(t.Number),
+    timestamps: threadTimestampsValidator,
+  });
+
+export const legacyThreadInfoValidator: TUnion<
+  LegacyThinRawThreadInfo | LegacyThickRawThreadInfo,
+> = t.union([
+  legacyThinRawThreadInfoValidator,
+  legacyThickRawThreadInfoValidator,
+]);
+
 export type MixedRawThreadInfos = {
   +[id: string]: LegacyRawThreadInfo | RawThreadInfo,
 };
diff --git a/lib/types/validators/redux-state-validators.js b/lib/types/validators/redux-state-validators.js
--- a/lib/types/validators/redux-state-validators.js
+++ b/lib/types/validators/redux-state-validators.js
@@ -2,7 +2,7 @@
 
 import t, { type TInterface } from 'tcomb';
 
-import { mixedThinRawThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
+import { rawThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
 import { tShape, tID } from '../../utils/validation-utils.js';
 import { entryStoreValidator } from '../entry-types.js';
 import { inviteLinksStoreValidator } from '../link-types.js';
@@ -22,7 +22,7 @@
 
 export const threadStoreValidator: TInterface<ThreadStore> =
   tShape<ThreadStore>({
-    threadInfos: t.dict(tID, mixedThinRawThreadInfoValidator),
+    threadInfos: t.dict(tID, rawThreadInfoValidator),
   });
 
 export const initialReduxStateValidator: TInterface<ServerWebInitialReduxStateResponse> =
diff --git a/lib/types/validators/thread-validators.js b/lib/types/validators/thread-validators.js
--- a/lib/types/validators/thread-validators.js
+++ b/lib/types/validators/thread-validators.js
@@ -3,7 +3,7 @@
 import t from 'tcomb';
 import type { TInterface } from 'tcomb';
 
-import { mixedThinRawThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
+import { mixedThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
 import { tShape, tID } from '../../utils/validation-utils.js';
 import { mediaValidator } from '../media-types.js';
 import {
@@ -69,7 +69,7 @@
 
 export const roleModificationResultValidator: TInterface<RoleModificationResult> =
   tShape<RoleModificationResult>({
-    threadInfo: t.maybe(mixedThinRawThreadInfoValidator),
+    threadInfo: mixedThreadInfoValidator,
     updatesResult: tShape({
       newUpdates: t.list(serverUpdateInfoValidator),
     }),
@@ -77,7 +77,7 @@
 
 export const roleDeletionResultValidator: TInterface<RoleDeletionResult> =
   tShape<RoleDeletionResult>({
-    threadInfo: t.maybe(mixedThinRawThreadInfoValidator),
+    threadInfo: mixedThreadInfoValidator,
     updatesResult: tShape({
       newUpdates: t.list(serverUpdateInfoValidator),
     }),
diff --git a/lib/types/validators/user-validators.js b/lib/types/validators/user-validators.js
--- a/lib/types/validators/user-validators.js
+++ b/lib/types/validators/user-validators.js
@@ -3,7 +3,7 @@
 import t, { type TInterface, type TUnion, type TEnums } from 'tcomb';
 
 import { policyTypeValidator } from '../../facts/policies.js';
-import { mixedThinRawThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
+import { mixedThreadInfoValidator } from '../../permissions/minimally-encoded-raw-thread-info-validators.js';
 import { tShape, tID, tUserID } from '../../utils/validation-utils.js';
 import type {
   LogOutResponse,
@@ -38,7 +38,7 @@
     rawMessageInfos: t.list(rawMessageInfoValidator),
     currentUserInfo: loggedInUserInfoValidator,
     cookieChange: tShape({
-      threadInfos: t.dict(tID, mixedThinRawThreadInfoValidator),
+      threadInfos: t.dict(tID, mixedThreadInfoValidator),
       userInfos: t.list(userInfoValidator),
     }),
   });
@@ -57,7 +57,7 @@
     rawEntryInfos: t.maybe(t.list(rawEntryInfoValidator)),
     serverTime: t.Number,
     cookieChange: tShape({
-      threadInfos: t.dict(tID, mixedThinRawThreadInfoValidator),
+      threadInfos: t.dict(tID, mixedThreadInfoValidator),
       userInfos: t.list(userInfoValidator),
     }),
     notAcknowledgedPolicies: t.maybe(t.list<TEnums>(policyTypeValidator)),
diff --git a/lib/utils/user-info-extraction-utils.js b/lib/utils/user-info-extraction-utils.js
--- a/lib/utils/user-info-extraction-utils.js
+++ b/lib/utils/user-info-extraction-utils.js
@@ -5,7 +5,7 @@
 
 import { processNewUserIDsActionType } from '../actions/user-actions.js';
 import type { CallSingleKeyserverEndpointResponse } from '../keyserver-conn/call-single-keyserver-endpoint.js';
-import { mixedThinRawThreadInfoValidator } from '../permissions/minimally-encoded-raw-thread-info-validators.js';
+import { mixedThreadInfoValidator } from '../permissions/minimally-encoded-raw-thread-info-validators.js';
 import type { Endpoint } from '../types/endpoints.js';
 import type { Dispatch } from '../types/redux-types.js';
 import type { MixedRawThreadInfos } from '../types/thread-types.js';
@@ -33,7 +33,7 @@
 const additionalResponseFieldsValidator = tShape<AdditionalResponseFields>({
   cookieChange: t.maybe(
     tShape<AdditionalCookieChange>({
-      threadInfos: t.dict(tID, mixedThinRawThreadInfoValidator),
+      threadInfos: t.dict(tID, mixedThreadInfoValidator),
       userInfos: t.list(userInfoValidator),
       cookieInvalidated: t.maybe(t.Boolean),
       sessionID: t.maybe(t.String),