diff --git a/ui/ceval/src/engines/engines.ts b/ui/ceval/src/engines/engines.ts
index c4d876724ebff..982382d5776a7 100644
--- a/ui/ceval/src/engines/engines.ts
+++ b/ui/ceval/src/engines/engines.ts
@@ -1,11 +1,11 @@
-import type { BrowserEngineInfo, ExternalEngineInfo, EngineInfo, CevalEngine, Requires } from '../types';
+import type { BrowserEngineInfo, ExternalEngineInfo, EngineInfo, CevalEngine } from '../types';
 import type CevalCtrl from '../ctrl';
 import { SimpleEngine } from './simpleEngine';
 import { StockfishWebEngine } from './stockfishWebEngine';
 import { ThreadedEngine } from './threadedEngine';
 import { ExternalEngine } from './externalEngine';
 import { storedStringProp, StoredProp } from 'common/storage';
-import { isAndroid, isIOS, isIPad, getFirefoxMajorVersion, features, type Feature } from 'common/device';
+import { isAndroid, isIOS, isIPad, features as browserSupport, type Feature } from 'common/device';
 import { xhrHeader } from 'common/xhr';
 import { lichessRules } from 'chessops/compat';
 import { log } from 'common/permalog';
@@ -16,12 +16,8 @@ export class Engines {
   localEngineMap: Map<string, WithMake>;
   externalEngines: ExternalEngineInfo[];
   selectProp: StoredProp<string>;
-  browserSupport: Requires[] = features().slice();
 
   constructor(private ctrl: CevalCtrl) {
-    const firefox = getFirefoxMajorVersion();
-    if (!firefox || firefox > 113) this.browserSupport.push('allowLsfw');
-
     this.localEngineMap = this.makeEngineMap();
     this.localEngines = [...this.localEngineMap.values()].map(e => e.info);
     this.externalEngines = this.ctrl.opts.externalEngines?.map(e => ({ tech: 'EXTERNAL', ...e })) ?? [];
@@ -47,7 +43,7 @@ export class Engines {
         name: 'Fairy Stockfish 14+ NNUE',
         short: 'FSF 14+',
         tech: 'NNUE',
-        requires: ['simd', 'allowLsfw'],
+        requires: ['simd', 'dynamicImportFromWorker'],
         variants: [key],
         assets: {
           version: 'sfw006',
@@ -75,7 +71,7 @@ export class Engines {
             name: 'Stockfish 16 NNUE · 7MB',
             short: 'SF 16 · 7MB',
             tech: 'NNUE',
-            requires: ['simd', 'allowLsfw'],
+            requires: ['simd', 'dynamicImportFromWorker'],
             minMem: 1536,
             assets: {
               version: 'sfw006',
@@ -91,7 +87,7 @@ export class Engines {
             name: 'Stockfish 17 NNUE · 79MB',
             short: 'SF 17 · 79MB',
             tech: 'NNUE',
-            requires: ['simd', 'allowLsfw'],
+            requires: ['simd', 'dynamicImportFromWorker'],
             minMem: 2560,
             assets: {
               version: 'sfw006',
@@ -126,7 +122,7 @@ export class Engines {
             name: 'Fairy Stockfish 14+ HCE',
             short: 'FSF 14+',
             tech: 'HCE',
-            requires: ['simd', 'allowLsfw'],
+            requires: ['simd', 'dynamicImportFromWorker'],
             variants: variants.map(v => v[0]),
             assets: {
               version: 'sfw006',
@@ -214,8 +210,8 @@ export class Engines {
       ]
         .filter(
           e =>
-            e.info.requires.every((req: Requires) => this.browserSupport.includes(req)) &&
-            !(e.info.obsoletedBy && this.browserSupport.includes(e.info.obsoletedBy as Feature)),
+            e.info.requires.every((req: Feature) => browserSupport().includes(req)) &&
+            !(e.info.obsoletedBy && browserSupport().includes(e.info.obsoletedBy as Feature)),
         )
         .map(e => [e.info.id, { info: withDefaults(e.info as BrowserEngineInfo), make: e.make }]),
     );
diff --git a/ui/ceval/src/types.ts b/ui/ceval/src/types.ts
index bfd85f1d34ca4..526a19ab2c9c4 100644
--- a/ui/ceval/src/types.ts
+++ b/ui/ceval/src/types.ts
@@ -34,7 +34,7 @@ export interface BaseEngineInfo {
   minThreads?: number;
   maxThreads?: number;
   maxHash?: number;
-  requires?: Requires[];
+  requires?: Feature[];
 }
 
 export interface ExternalEngineInfo extends BaseEngineInfo {
@@ -46,14 +46,12 @@ export interface ExternalEngineInfo extends BaseEngineInfo {
 export interface BrowserEngineInfo extends BaseEngineInfo {
   minMem?: number;
   assets: { root?: string; js?: string; wasm?: string; version?: string; nnue?: string[] };
-  requires: Requires[];
+  requires: Feature[];
   obsoletedBy?: Feature;
 }
 
 export type EngineInfo = BrowserEngineInfo | ExternalEngineInfo;
 
-export type Requires = Feature | 'allowLsfw'; // lsfw = lila-stockfish-web
-
 export type EngineNotifier = (status?: {
   download?: { bytes: number; total: number };
   error?: string;
diff --git a/ui/common/src/device.ts b/ui/common/src/device.ts
index 3826875adff52..616ef24a2e8c2 100644
--- a/ui/common/src/device.ts
+++ b/ui/common/src/device.ts
@@ -99,7 +99,7 @@ export const isApple: () => boolean = memoize<boolean>(
 
 export const shareIcon: () => string = () => (isApple() ? licon.ShareIos : licon.ShareAndroid);
 
-export type Feature = 'wasm' | 'sharedMem' | 'simd';
+export type Feature = 'wasm' | 'sharedMem' | 'simd' | 'dynamicImportFromWorker';
 
 export const hasFeature = (feat?: string): boolean => !feat || features().includes(feat as Feature);
 
@@ -121,6 +121,16 @@ export const features: () => readonly Feature[] = memoize<readonly Feature[]>(()
       ]);
       if (WebAssembly.validate(sourceWithSimd)) features.push('simd');
     }
+    try {
+      new Worker(
+        URL.createObjectURL(
+          new Blob(["import('data:text/javascript,export default {}')"], { type: 'application/javascript' }),
+        ),
+      ).terminate();
+      features.push('dynamicImportFromWorker');
+    } catch {
+      // no dynamic import from worker
+    }
   }
   return Object.freeze(features);
 });
diff --git a/ui/puzzle/src/report.ts b/ui/puzzle/src/report.ts
index 34947bcafaba6..6cb96ded6c143 100644
--- a/ui/puzzle/src/report.ts
+++ b/ui/puzzle/src/report.ts
@@ -32,7 +32,9 @@ export default class Report {
       // the `mate` key theme is not sent, as it is considered redubant with `mateInX`
       ctrl.data.puzzle.themes.some((t: ThemeKey) => t.toLowerCase().includes('mate')) ||
       // if the user has chosen to hide the dialog less than a week ago
-      this.tsHideReportDialog() > Date.now() - 1000 * 3600 * 24 * 7
+      this.tsHideReportDialog() > Date.now() - 1000 * 3600 * 24 * 7 ||
+      // dynamic import from web worker feature is shared by all stockfish 16+ WASMs
+      !ctrl.ceval.engines.active?.requires?.includes('dynamicImportFromWorker')
     )
       return;
     const node = ctrl.node;