Disable thread by reference by default for Play Store version

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

@@ -1067,6 +1067,9 @@ public class ApplicationEx extends Application
                 editor.putBoolean("beige", false);
         }
 
+        if (version < 2259)
+            editor.putBoolean("thread_byref", true);
+
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && !BuildConfig.DEBUG)
             editor.remove("background_service");
 

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

@@ -2617,7 +2617,7 @@ public class FragmentOptionsMisc extends FragmentBase implements SharedPreferenc
             swTldFlags.setChecked(prefs.getBoolean("tld_flags", false));
             swJsonLd.setChecked(prefs.getBoolean("json_ld", false));
             swDupMsgId.setChecked(prefs.getBoolean("dup_msgids", false));
-            swThreadByRef.setChecked(prefs.getBoolean("thread_byref", true));
+            swThreadByRef.setChecked(prefs.getBoolean("thread_byref", !Helper.isPlayStoreInstall()));
             swSaveUserFlags.setChecked(prefs.getBoolean("save_user_flags", false));
             swMdn.setChecked(prefs.getBoolean("mdn", swExperiments.isChecked()));
             swAppChooser.setChecked(prefs.getBoolean("app_chooser", false));

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

@@ -1940,7 +1940,7 @@ public class MessageHelper {
         }
 
         // Common reference
-        boolean thread_byref = prefs.getBoolean("thread_byref", true);
+        boolean thread_byref = prefs.getBoolean("thread_byref", !Helper.isPlayStoreInstall());
         if (thread == null && refs.size() > 0 && thread_byref) {
             // For example
             //   Message-ID: <organization/project/pull/nnn/issue_event/xxx@github.com>