diff --git a/app/soapbox/utils/__tests__/features.test.ts b/app/soapbox/utils/__tests__/features.test.ts
index 3ba9c90ba..f214393d0 100644
--- a/app/soapbox/utils/__tests__/features.test.ts
+++ b/app/soapbox/utils/__tests__/features.test.ts
@@ -40,6 +40,7 @@ describe('parseVersion', () => {
       software: 'TruthSocial',
       version: '1.0.0',
       compatVersion: '3.4.1',
+      build: 'nightly-20230627',
     });
   });
 
@@ -62,6 +63,15 @@ describe('parseVersion', () => {
       build: 'cofe',
     });
   });
+
+  it('with Mastodon nightly build', () => {
+    const version = '4.1.2+nightly-20230627';
+    expect(parseVersion(version)).toEqual({
+      software: 'Mastodon',
+      version: '4.1.2',
+      compatVersion: '4.1.2',
+    });
+  });
 });
 
 describe('getFeatures', () => {
diff --git a/app/soapbox/utils/features.ts b/app/soapbox/utils/features.ts
index 77ba331cb..126248e5d 100644
--- a/app/soapbox/utils/features.ts
+++ b/app/soapbox/utils/features.ts
@@ -992,7 +992,7 @@ interface Backend {
 
 /** Get information about the software from its version string */
 export const parseVersion = (version: string): Backend => {
-  const regex = /^([\w+.]*)(?: \(compatible; ([\w]*) (.*)\))?$/;
+  const regex = /^([\w+.-]*)(?: \(compatible; ([\w]*) (.*)\))?$/;
   const match = regex.exec(version);
 
   const semverString = match && (match[3] || match[1]);