diff --git a/client/app/collections/collections.ts b/client/app/collections/collections.ts
index ac9f05d..bdf9628 100644
--- a/client/app/collections/collections.ts
+++ b/client/app/collections/collections.ts
@@ -16,7 +16,7 @@
 //
 import {HttpErrorResponse} from '@angular/common/http';
 import {ChangeDetectionStrategy, Component, ElementRef, Inject, OnDestroy, OnInit, ViewChild} from '@angular/core';
-import {FormControl, FormGroupDirective, NgForm} from '@angular/forms';
+import {UntypedFormControl, FormGroupDirective, NgForm} from '@angular/forms';
 import {ErrorStateMatcher} from '@angular/material/core';
 import {MatSnackBar} from '@angular/material/snack-bar';
 import {Router} from '@angular/router';
@@ -157,7 +157,7 @@ export class Collections implements OnInit, OnDestroy {
 }
 
 class DisabledErrorStateMatcher implements ErrorStateMatcher {
-  isErrorState(control: FormControl|null, form: FormGroupDirective|NgForm|null):
+  isErrorState(control: UntypedFormControl|null, form: FormGroupDirective|NgForm|null):
       boolean {
     return false;
   }
diff --git a/client/app/sidebar/settings_menu/settings_menu.ts b/client/app/sidebar/settings_menu/settings_menu.ts
index 6c38695..5c5730a 100644
--- a/client/app/sidebar/settings_menu/settings_menu.ts
+++ b/client/app/sidebar/settings_menu/settings_menu.ts
@@ -16,7 +16,7 @@
 //
 import {CdkDragDrop, moveItemInArray} from '@angular/cdk/drag-drop';
 import {ChangeDetectionStrategy, ChangeDetectorRef, Component, Input, OnInit} from '@angular/core';
-import {FormControl} from '@angular/forms';
+import {UntypedFormControl} from '@angular/forms';
 import {ErrorStateMatcher} from '@angular/material/core';
 import {BehaviorSubject, merge} from 'rxjs';
 import {switchMap} from 'rxjs/operators';
@@ -31,7 +31,7 @@ import {getHumanReadableDurationFromNs, timeInputToNs} from '../../util/duration
  * Matcher which enters an error state immediately, ignoring empty fields.
  */
 class ImmediateErrorStateMatcher implements ErrorStateMatcher {
-  isErrorState(control: FormControl|null): boolean {
+  isErrorState(control: UntypedFormControl|null): boolean {
     if (!control) {
       return false;
     }
diff --git a/client/app/sidebar/thread_table/thread_table.ts b/client/app/sidebar/thread_table/thread_table.ts
index 044bd19..eb21988 100644
--- a/client/app/sidebar/thread_table/thread_table.ts
+++ b/client/app/sidebar/thread_table/thread_table.ts
@@ -16,7 +16,7 @@
 //
 import {animate, state, style, transition, trigger} from '@angular/animations';
 import {AfterViewInit, ChangeDetectionStrategy, ChangeDetectorRef, Component, Input, OnInit} from '@angular/core';
-import {FormControl} from '@angular/forms';
+import {UntypedFormControl} from '@angular/forms';
 import {ErrorStateMatcher} from '@angular/material/core';
 import {BehaviorSubject, Observable} from 'rxjs';
 
@@ -33,7 +33,7 @@ const EMBEDDED_PAGE_SIZE = 20;
  * Matcher which enters an error state immediately, ignoring empty fields.
  */
 class ImmediateErrorStateMatcher implements ErrorStateMatcher {
-  isErrorState(control: FormControl|null): boolean {
+  isErrorState(control: UntypedFormControl|null): boolean {
     if (!control) {
       return false;
     }