diff --git a/src/App.spec.ts b/src/App.spec.ts
index c17ee817a..6329a90a6 100644
--- a/src/App.spec.ts
+++ b/src/App.spec.ts
@@ -92,7 +92,7 @@ describe('App', () => {
       try {
         new App({ signingSecret: '' }); // eslint-disable-line @typescript-eslint/no-unused-expressions
         assert.fail();
-      } catch (error) {
+      } catch (error: any) {
         // Assert
         assert.propertyVal(error, 'code', ErrorCode.AppInitializationError);
       }
@@ -107,7 +107,7 @@ describe('App', () => {
         // eslint-disable-line @typescript-eslint/no-unused-expressions
         new App({ token: '', authorize: authorizeCallback, signingSecret: '' });
         assert.fail();
-      } catch (error) {
+      } catch (error: any) {
         // Assert
         assert.propertyVal(error, 'code', ErrorCode.AppInitializationError);
         assert(authorizeCallback.notCalled);
@@ -123,7 +123,7 @@ describe('App', () => {
         // eslint-disable-line @typescript-eslint/no-unused-expressions
         new App({ token: '', clientId: '', clientSecret: '', stateSecret: '', signingSecret: '' });
         assert.fail();
-      } catch (error) {
+      } catch (error: any) {
         // Assert
         assert.propertyVal(error, 'code', ErrorCode.AppInitializationError);
         assert(authorizeCallback.notCalled);
@@ -139,7 +139,7 @@ describe('App', () => {
         // eslint-disable-line @typescript-eslint/no-unused-expressions
         new App({ authorize: authorizeCallback, clientId: '', clientSecret: '', stateSecret: '', signingSecret: '' });
         assert.fail();
-      } catch (error) {
+      } catch (error: any) {
         // Assert
         assert.propertyVal(error, 'code', ErrorCode.AppInitializationError);
         assert(authorizeCallback.notCalled);
@@ -165,7 +165,7 @@ describe('App', () => {
       try {
         new App({ authorize: noopAuthorize }); // eslint-disable-line @typescript-eslint/no-unused-expressions
         assert.fail();
-      } catch (error) {
+      } catch (error: any) {
         // Assert
         assert.propertyVal(error, 'code', ErrorCode.AppInitializationError);
       }
@@ -180,7 +180,7 @@ describe('App', () => {
         // eslint-disable-line @typescript-eslint/no-unused-expressions
         new App({ token: '', signingSecret: '', socketMode: true, receiver: fakeReceiver });
         assert.fail();
-      } catch (error) {
+      } catch (error: any) {
         // Assert
         assert.propertyVal(error, 'code', ErrorCode.AppInitializationError);
       }
@@ -476,7 +476,7 @@ describe('App', () => {
         app.use(async ({ next }) => {
           try {
             await next!();
-          } catch (err) {
+          } catch (err: any) {
             caughtError = err;
           }
         });
@@ -560,7 +560,7 @@ describe('App', () => {
 
         try {
           await fakeReceiver.sendEvent(dummyReceiverEvent);
-        } catch (err) {
+        } catch (err: any) {
           actualError = err;
         }
 
diff --git a/src/App.ts b/src/App.ts
index 9f04babf5..7403fa6d3 100644
--- a/src/App.ts
+++ b/src/App.ts
@@ -676,9 +676,10 @@ export default class App {
         authorizeResult = await this.authorize(source as AuthorizeSourceData<false>, bodyArg);
       }
     } catch (error) {
+      const e = error as any;
       this.logger.warn('Authorization of incoming event did not succeed. No listeners will be called.');
-      error.code = 'slack_bolt_authorization_error';
-      return this.handleError(error);
+      e.code = 'slack_bolt_authorization_error';
+      return this.handleError(e);
     }
 
     // Try to set teamId from AuthorizeResult before using one from source
@@ -854,7 +855,8 @@ export default class App {
         },
       );
     } catch (error) {
-      return this.handleError(error);
+      const e = error as any;
+      return this.handleError(e);
     }
   }
 
diff --git a/src/conversation-store.spec.ts b/src/conversation-store.spec.ts
index e3e989ba8..5ed3f3551 100644
--- a/src/conversation-store.spec.ts
+++ b/src/conversation-store.spec.ts
@@ -163,7 +163,7 @@ describe('MemoryStore', () => {
       try {
         await store.get('CONVERSATION_ID');
         assert.fail();
-      } catch (error) {
+      } catch (error: any) {
         // Assert
         assert.instanceOf(error, Error);
         assert.notInstanceOf(error, AssertionError);
@@ -184,7 +184,7 @@ describe('MemoryStore', () => {
       try {
         await store.get(dummyConversationId);
         assert.fail();
-      } catch (error) {
+      } catch (error: any) {
         // Assert
         assert.instanceOf(error, Error);
         assert.notInstanceOf(error, AssertionError);
diff --git a/src/conversation-store.ts b/src/conversation-store.ts
index f5a4d0a14..4cd142154 100644
--- a/src/conversation-store.ts
+++ b/src/conversation-store.ts
@@ -64,9 +64,10 @@ export function conversationContext<ConversationState = any>(
         context.conversation = await store.get(conversationId);
         logger.debug(`Conversation context loaded for ID: ${conversationId}`);
       } catch (error) {
-        if (error.message !== undefined && error.message !== 'Conversation not found') {
+        const e = error as any;
+        if (e.message !== undefined && e.message !== 'Conversation not found') {
           // The conversation data can be expired - error: Conversation expired
-          logger.debug(`Conversation context failed loading for ID: ${conversationId}, error: ${error.message}`);
+          logger.debug(`Conversation context failed loading for ID: ${conversationId}, error: ${e.message}`);
         }
       }
     } else {
diff --git a/src/middleware/builtin.spec.ts b/src/middleware/builtin.spec.ts
index 5f05a834c..329e54c8b 100644
--- a/src/middleware/builtin.spec.ts
+++ b/src/middleware/builtin.spec.ts
@@ -181,7 +181,7 @@ describe('directMention()', () => {
 
     try {
       await middleware(fakeArgs);
-    } catch (err) {
+    } catch (err: any) {
       error = err;
     }
 
@@ -308,7 +308,7 @@ describe('ignoreSelf()', () => {
     let error;
     try {
       await middleware(fakeArgs);
-    } catch (err) {
+    } catch (err: any) {
       error = err;
     }
 
diff --git a/src/receivers/ExpressReceiver.spec.ts b/src/receivers/ExpressReceiver.spec.ts
index 7fc36a19c..1ecda7336 100644
--- a/src/receivers/ExpressReceiver.spec.ts
+++ b/src/receivers/ExpressReceiver.spec.ts
@@ -166,7 +166,7 @@ describe('ExpressReceiver', function () {
       let caughtError: Error | undefined;
       try {
         await receiver.start(port);
-      } catch (error) {
+      } catch (error: any) {
         caughtError = error;
       }
 
@@ -188,7 +188,7 @@ describe('ExpressReceiver', function () {
       await receiver.start(port);
       try {
         await receiver.start(port);
-      } catch (error) {
+      } catch (error: any) {
         caughtError = error;
       }
 
@@ -230,7 +230,7 @@ describe('ExpressReceiver', function () {
       let caughtError: Error | undefined;
       try {
         await receiver.stop();
-      } catch (error) {
+      } catch (error: any) {
         caughtError = error;
       }
 
diff --git a/src/receivers/HTTPReceiver.spec.ts b/src/receivers/HTTPReceiver.spec.ts
index 02f2e3573..685e8eb37 100644
--- a/src/receivers/HTTPReceiver.spec.ts
+++ b/src/receivers/HTTPReceiver.spec.ts
@@ -71,6 +71,8 @@ describe('HTTPReceiver', function () {
       });
       assert.isNotNull(receiver);
     });
+  });
+  describe('request handling', function () {
     it('should invoke installer generateInstallUrl if a request comes into the install path', async function () {
       // Arrange
       const installProviderStub = sinon.createStubInstance(InstallProvider);
@@ -113,7 +115,7 @@ describe('HTTPReceiver', function () {
       assert(installProviderStub.generateInstallUrl.calledWith(sinon.match({ metadata, scopes, userScopes })));
       assert.isTrue(writeHead.calledWith(200));
     });
-    it('should rediect installers if directInstallEnabled is true', async function () {
+    it('should redirect installers if directInstallEnabled is true', async function () {
       // Arrange
       const installProviderStub = sinon.createStubInstance(InstallProvider);
       const overrides = mergeOverrides(
@@ -156,7 +158,52 @@ describe('HTTPReceiver', function () {
       assert(installProviderStub.generateInstallUrl.calledWith(sinon.match({ metadata, scopes, userScopes })));
       assert.isTrue(writeHead.calledWith(302, sinon.match.object));
     });
-    it('should return a 404 if a request comes into neither the install path nor the redirect URI path', async function () {
+    it('should invoke installer handler if a request comes into the redirect URI path', async function () {
+      // Arrange
+      const installProviderStub = sinon.createStubInstance(InstallProvider, {
+        handleCallback: sinon.stub().resolves() as unknown as Promise<void>,
+      });
+      const overrides = mergeOverrides(
+        withHttpCreateServer(this.fakeCreateServer),
+        withHttpsCreateServer(sinon.fake.throws('Should not be used.')),
+      );
+      const HTTPReceiver = await importHTTPReceiver(overrides);
+
+      const metadata = 'this is bat country';
+      const scopes = ['channels:read'];
+      const userScopes = ['chat:write'];
+      const callbackOptions = {};
+      const receiver = new HTTPReceiver({
+        logger: noopLogger,
+        clientId: 'my-clientId',
+        clientSecret: 'my-client-secret',
+        signingSecret: 'secret',
+        stateSecret: 'state-secret',
+        scopes,
+        installerOptions: {
+          authVersion: 'v2',
+          redirectUriPath: '/heyo',
+          callbackOptions,
+          metadata,
+          userScopes,
+        },
+      });
+      assert.isNotNull(receiver);
+      receiver.installer = installProviderStub as unknown as InstallProvider;
+      const fakeReq: IncomingMessage = sinon.createStubInstance(IncomingMessage) as IncomingMessage;
+      fakeReq.url = '/heyo';
+      fakeReq.headers = { host: 'localhost' };
+      fakeReq.method = 'GET';
+      const fakeRes: ServerResponse & {} = sinon.createStubInstance(ServerResponse) as unknown as ServerResponse;
+      const writeHead = sinon.fake();
+      const end = sinon.fake();
+      fakeRes.writeHead = writeHead;
+      fakeRes.end = end;
+      /* eslint-disable-next-line @typescript-eslint/await-thenable */
+      await receiver.requestListener(fakeReq, fakeRes);
+      assert(installProviderStub.handleCallback.calledWith(fakeReq, fakeRes, callbackOptions));
+    });
+    it('should throw if a request comes into neither the install path nor the redirect URI path', async function () {
       // Arrange
       const installProviderStub = sinon.createStubInstance(InstallProvider);
       const overrides = mergeOverrides(
diff --git a/src/receivers/HTTPReceiver.ts b/src/receivers/HTTPReceiver.ts
index 851169dc4..f0ea153bf 100644
--- a/src/receivers/HTTPReceiver.ts
+++ b/src/receivers/HTTPReceiver.ts
@@ -166,13 +166,14 @@ export default class HTTPReceiver implements Receiver {
       try {
         this.requestListener(req, res);
       } catch (error) {
-        if (error.code === ErrorCode.HTTPReceiverDeferredRequestError) {
+        const e = error as any;
+        if (e.code === ErrorCode.HTTPReceiverDeferredRequestError) {
           this.logger.info('An unhandled request was ignored');
           res.writeHead(404);
           res.end();
         } else {
           this.logger.error('An unexpected error was encountered');
-          this.logger.debug(`Error details: ${error}`);
+          this.logger.debug(`Error details: ${e}`);
           res.writeHead(500);
           res.end();
         }
@@ -276,7 +277,8 @@ export default class HTTPReceiver implements Receiver {
       try {
         bufferedReq = await verifySlackAuthenticity({ signingSecret: this.signingSecret }, req);
       } catch (err) {
-        this.logger.warn(`Request verification failed: ${err.message}`);
+        const e = err as any;
+        this.logger.warn(`Request verification failed: ${e.message}`);
         res.writeHead(401);
         res.end();
         return;
@@ -289,7 +291,8 @@ export default class HTTPReceiver implements Receiver {
       try {
         body = parseBody(bufferedReq);
       } catch (err) {
-        this.logger.warn(`Malformed request body: ${err.message}`);
+        const e = err as any;
+        this.logger.warn(`Malformed request body: ${e.message}`);
         res.writeHead(400);
         res.end();
         return;
@@ -370,8 +373,9 @@ export default class HTTPReceiver implements Receiver {
           this.logger.debug('stored response sent');
         }
       } catch (err) {
+        const e = err as any;
         this.logger.error('An unhandled error occurred while Bolt processed an event');
-        this.logger.debug(`Error details: ${err}, storedResponse: ${storedResponse}`);
+        this.logger.debug(`Error details: ${e}, storedResponse: ${storedResponse}`);
         res.writeHead(500);
         res.end();
       }
@@ -412,8 +416,9 @@ export default class HTTPReceiver implements Receiver {
           res.end(body);
         }
       } catch (err) {
+        const e = err as any;
         this.logger.error('An unhandled error occurred while Bolt processed a request to the installation path');
-        this.logger.debug(`Error details: ${err}`);
+        this.logger.debug(`Error details: ${e}`);
       }
     })();
   }
diff --git a/src/receivers/SocketModeReceiver.ts b/src/receivers/SocketModeReceiver.ts
index 3a206a74f..89e2facc3 100644
--- a/src/receivers/SocketModeReceiver.ts
+++ b/src/receivers/SocketModeReceiver.ts
@@ -123,7 +123,8 @@ export default class SocketModeReceiver implements Receiver {
               res.end(renderHtmlForInstallPath(url));
             }
           } catch (err) {
-            throw new Error(err);
+            const e = err as any;
+            throw new Error(e);
           }
         } else {
           this.logger.error(`Tried to reach ${req.url} which isn't a valid route.`);