Check for third party build

FAQ.md

@@ -261,6 +261,7 @@ Fonts, sizes, colors, etc should be material design whenever possible.
 * [(144) How can I record voice notes?](#user-content-faq144)
 * [(145) How can I set a notification sound for an account, folder or sender?](#user-content-faq145)
 * [(146) How can I fix incorrect message times?](#user-content-faq146)
+* [(147) What should I know about third party versions?](#user-content-faq147)
 
 [I have another question.](#user-content-support)
 
@@ -2781,6 +2782,25 @@ To solve this, long press the folder(s) in the folder list and select *Delete lo
 
 <br />
 
+<a name="faq147"></a>
+**(147) What should I know about third party versions?**
+
+You likely came here because you are using a third party build of FairEmail.
+
+The F-Droid build is supported, but any other unofficial build is not supported.
+
+F-Droid builds irregularly, which can be problematic when there is an important update.
+Therefore you are advised to switch to the GitHub release.
+
+Note that the GitHub version will automatically check for updates.
+When desired, this can be turned off in the miscellaneous settings.
+
+Please [see here](https://github.com/M66B/FairEmail/blob/master/README.md#user-content-downloads) for all download options.
+
+If you have a problem with the F-Droid build, please check if there is a newer version first.
+
+<br>
+
 ## Support
 
 Requested features should:

app/src/main/java/eu/faircode/email/FragmentMessages.java

@@ -2843,7 +2843,8 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
             fabMore.hide();
 
         if (!checkReporting())
-            checkReview();
+            if (!checkReview())
+                checkFingerprint();
     }
 
     @Override
@@ -2985,7 +2986,6 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                 prefs.edit().putBoolean("crash_reports_asked", true).apply();
             }
         });
-
         snackbar.show();
 
         return true;
@@ -3045,7 +3045,28 @@ public class FragmentMessages extends FragmentBase implements SharedPreferences.
                 prefs.edit().putLong("review_later", new Date().getTime()).apply();
             }
         });
+        snackbar.show();
+
+        return true;
+    }
+
+    private boolean checkFingerprint() {
+        if (Helper.hasValidFingerprint(getContext()))
+            return false;
+
+        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getContext());
+        if (prefs.getBoolean("third_party_notified", false))
+            return false;
 
+        final Snackbar snackbar = Snackbar.make(view, R.string.title_third_party, Snackbar.LENGTH_INDEFINITE);
+        snackbar.setAction(R.string.title_info, new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                snackbar.dismiss();
+                Helper.viewFAQ(getContext(), 147);
+                prefs.edit().putBoolean("third_party_notified", true).apply();
+            }
+        });
         snackbar.show();
 
         return true;

app/src/main/res/values/strings.xml

@@ -738,6 +738,8 @@
         This will help to maintain a balance between unfavorable and favorable reviews.
     </string>
 
+    <string name="title_third_party">You are using a version of a third party</string>
+
     <string name="title_expand_warning">Expanding this message will download %1$s</string>
     <string name="title_download_message">Downloading &#8230;</string>