diff --git a/keyserver/src/responders/entry-responders.js b/keyserver/src/responders/entry-responders.js
--- a/keyserver/src/responders/entry-responders.js
+++ b/keyserver/src/responders/entry-responders.js
@@ -128,7 +128,6 @@
 export const createEntryRequestInputValidator: TInterface<CreateEntryRequest> =
   tShape<CreateEntryRequest>({
     text: t.String,
-    sessionID: t.maybe(t.String),
     timestamp: t.Number,
     date: tDate,
     threadID: tID,
@@ -148,7 +147,6 @@
     entryID: tID,
     text: t.String,
     prevText: t.String,
-    sessionID: t.maybe(t.String),
     timestamp: t.Number,
     calendarQuery: t.maybe(calendarQueryValidator),
   });
@@ -164,7 +162,6 @@
   tShape<DeleteEntryRequest>({
     entryID: tID,
     prevText: t.String,
-    sessionID: t.maybe(t.String),
     timestamp: t.Number,
     calendarQuery: t.maybe(calendarQueryValidator),
   });
@@ -179,7 +176,6 @@
 export const restoreEntryRequestInputValidator: TInterface<RestoreEntryRequest> =
   tShape<RestoreEntryRequest>({
     entryID: tID,
-    sessionID: t.maybe(t.String),
     timestamp: t.Number,
     calendarQuery: t.maybe(calendarQueryValidator),
   });
diff --git a/keyserver/src/responders/thread-responders.js b/keyserver/src/responders/thread-responders.js
--- a/keyserver/src/responders/thread-responders.js
+++ b/keyserver/src/responders/thread-responders.js
@@ -34,7 +34,6 @@
   tShape,
   tNumEnum,
   tColor,
-  tPassword,
   tID,
   tUserID,
 } from 'lib/utils/validation-utils.js';
@@ -58,7 +57,6 @@
 export const threadDeletionRequestInputValidator: TInterface<ThreadDeletionRequest> =
   tShape<ThreadDeletionRequest>({
     threadID: tID,
-    accountPassword: t.maybe(tPassword),
   });
 
 async function threadDeletionResponder(
@@ -125,7 +123,6 @@
       newMemberIDs: t.maybe(t.list(tUserID)),
       avatar: t.maybe(updateUserAvatarRequestValidator),
     }),
-    accountPassword: t.maybe(tPassword),
   });
 
 async function threadUpdateResponder(
diff --git a/keyserver/src/responders/user-responders.js b/keyserver/src/responders/user-responders.js
--- a/keyserver/src/responders/user-responders.js
+++ b/keyserver/src/responders/user-responders.js
@@ -77,7 +77,6 @@
   getPublicKeyFromSIWEStatement,
   isValidSIWEMessage,
   isValidSIWEStatementWithPublicKey,
-  primaryIdentityPublicKeyRegex,
 } from 'lib/utils/siwe-utils.js';
 import {
   tShape,
@@ -85,7 +84,6 @@
   tPassword,
   tEmail,
   tOldValidUsername,
-  tRegex,
   tID,
   tUserID,
 } from 'lib/utils/validation-utils.js';
@@ -159,7 +157,6 @@
 export const accountUpdateInputValidator: TInterface<PasswordUpdate> =
   tShape<PasswordUpdate>({
     updatedFields: tShape({
-      email: t.maybe(tEmail),
       password: t.maybe(tPassword),
     }),
     currentPassword: tPassword,
@@ -217,14 +214,10 @@
 export const registerRequestInputValidator: TInterface<RegisterRequest> =
   tShape<RegisterRequest>({
     username: t.String,
-    email: t.maybe(tEmail),
     password: tPassword,
     calendarQuery: t.maybe(calendarQueryValidator),
     deviceTokenUpdateRequest: t.maybe(deviceTokenUpdateRequestInputValidator),
     platformDetails: tPlatformDetails,
-    // We include `primaryIdentityPublicKey` to avoid breaking
-    // old clients, but we no longer do anything with it.
-    primaryIdentityPublicKey: t.maybe(tRegex(primaryIdentityPublicKeyRegex)),
     signedIdentityKeysBlob: t.maybe(signedIdentityKeysBlobValidator),
     initialNotificationsEncryptedMessage: t.maybe(t.String),
   });
@@ -488,9 +481,6 @@
     deviceTokenUpdateRequest: t.maybe(deviceTokenUpdateRequestInputValidator),
     platformDetails: tPlatformDetails,
     source: t.maybe(t.enums.of(values(authActionSources))),
-    // We include `primaryIdentityPublicKey` to avoid breaking
-    // old clients, but we no longer do anything with it.
-    primaryIdentityPublicKey: t.maybe(tRegex(primaryIdentityPublicKeyRegex)),
     signedIdentityKeysBlob: t.maybe(signedIdentityKeysBlobValidator),
     initialNotificationsEncryptedMessage: t.maybe(t.String),
   });
diff --git a/lib/types/account-types.js b/lib/types/account-types.js
--- a/lib/types/account-types.js
+++ b/lib/types/account-types.js
@@ -68,12 +68,10 @@
 
 export type RegisterRequest = {
   +username: string,
-  +email?: empty,
   +password: string,
   +calendarQuery?: ?CalendarQuery,
   +deviceTokenUpdateRequest?: ?DeviceTokenUpdateRequest,
   +platformDetails: PlatformDetails,
-  +primaryIdentityPublicKey?: empty,
   +signedIdentityKeysBlob?: SignedIdentityKeysBlob,
   +initialNotificationsEncryptedMessage?: string,
 };
@@ -168,7 +166,6 @@
   +platformDetails: PlatformDetails,
   +watchedIDs: $ReadOnlyArray<string>,
   +source?: AuthActionSource,
-  +primaryIdentityPublicKey?: empty,
   +signedIdentityKeysBlob?: SignedIdentityKeysBlob,
   +initialNotificationsEncryptedMessage?: string,
 };
diff --git a/lib/types/entry-types.js b/lib/types/entry-types.js
--- a/lib/types/entry-types.js
+++ b/lib/types/entry-types.js
@@ -143,7 +143,6 @@
 
 export type SaveEntryRequest = {
   +entryID: string,
-  +sessionID?: empty,
   +text: string,
   +prevText: string,
   +timestamp: number,
@@ -178,7 +177,6 @@
 
 export type CreateEntryRequest = {
   +text: string,
-  +sessionID?: empty,
   +timestamp: number,
   +date: string,
   +threadID: string,
@@ -199,7 +197,6 @@
 
 export type DeleteEntryRequest = {
   +entryID: string,
-  +sessionID?: empty,
   +prevText: string,
   +timestamp: number,
   +calendarQuery?: CalendarQuery,
@@ -212,7 +209,6 @@
 
 export type RestoreEntryRequest = {
   +entryID: string,
-  +sessionID?: empty,
   +timestamp: number,
   +calendarQuery?: CalendarQuery,
 };
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
@@ -306,7 +306,6 @@
 
 export type ThreadDeletionRequest = {
   +threadID: string,
-  +accountPassword?: empty,
 };
 
 export type RemoveMembersRequest = {
@@ -363,7 +362,6 @@
 export type UpdateThreadRequest = {
   +threadID: string,
   +changes: ThreadChanges,
-  +accountPassword?: empty,
 };
 
 export type BaseNewThreadRequest = {
diff --git a/lib/types/user-types.js b/lib/types/user-types.js
--- a/lib/types/user-types.js
+++ b/lib/types/user-types.js
@@ -103,7 +103,6 @@
 export type PasswordUpdate = {
   +updatedFields: {
     +password?: ?string,
-    +email?: empty,
   },
   +currentPassword: string,
 };