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 +68,12 @@
 
 export type RegisterRequest = {
   +username: string,
-  +email?: empty,
+  +email?: string,
   +password: string,
   +calendarQuery?: ?CalendarQuery,
   +deviceTokenUpdateRequest?: ?DeviceTokenUpdateRequest,
   +platformDetails: PlatformDetails,
-  +primaryIdentityPublicKey?: empty,
+  +primaryIdentityPublicKey?: string,
   +signedIdentityKeysBlob?: SignedIdentityKeysBlob,
   +initialNotificationsEncryptedMessage?: string,
 };
@@ -168,7 +168,7 @@
   +platformDetails: PlatformDetails,
   +watchedIDs: $ReadOnlyArray<string>,
   +source?: AuthActionSource,
-  +primaryIdentityPublicKey?: empty,
+  +primaryIdentityPublicKey?: string,
   +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 +143,7 @@
 
 export type SaveEntryRequest = {
   +entryID: string,
-  +sessionID?: empty,
+  +sessionID?: string,
   +text: string,
   +prevText: string,
   +timestamp: number,
@@ -178,7 +178,7 @@
 
 export type CreateEntryRequest = {
   +text: string,
-  +sessionID?: empty,
+  +sessionID?: string,
   +timestamp: number,
   +date: string,
   +threadID: string,
@@ -199,7 +199,7 @@
 
 export type DeleteEntryRequest = {
   +entryID: string,
-  +sessionID?: empty,
+  +sessionID?: string,
   +prevText: string,
   +timestamp: number,
   +calendarQuery?: CalendarQuery,
@@ -212,7 +212,7 @@
 
 export type RestoreEntryRequest = {
   +entryID: string,
-  +sessionID?: empty,
+  +sessionID?: string,
   +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 +306,7 @@
 
 export type ThreadDeletionRequest = {
   +threadID: string,
-  +accountPassword?: empty,
+  +accountPassword?: string,
 };
 
 export type RemoveMembersRequest = {
@@ -363,7 +363,7 @@
 export type UpdateThreadRequest = {
   +threadID: string,
   +changes: ThreadChanges,
-  +accountPassword?: empty,
+  +accountPassword?: string,
 };
 
 export type BaseNewThreadRequest = {
@@ -384,7 +384,7 @@
       +type: 5,
       +sourceMessageID: string,
       ...BaseNewThreadRequest,
-      +parentThreadID: string,
+      +parentThreadID?: string,
     }>;
 
 export type ClientNewThinThreadRequest = $ReadOnly<{
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 +103,7 @@
 export type PasswordUpdate = {
   +updatedFields: {
     +password?: ?string,
-    +email?: empty,
+    +email?: string,
   },
   +currentPassword: string,
 };