Unzip requires Andoid O

Due to java.nio.file.LinkOption

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

@@ -25,6 +25,7 @@ import android.content.SharedPreferences;
 import android.graphics.Bitmap;
 import android.graphics.Color;
 import android.net.Uri;
+import android.os.Build;
 import android.os.Bundle;
 import android.text.SpannableStringBuilder;
 import android.text.Spanned;
@@ -178,6 +179,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
     private SwitchCompat swAuthenticationIndicator;
 
     private Group grpGravatars;
+    private Group grpUnzip;
 
     private NumberFormat NF = NumberFormat.getNumberInstance();
 
@@ -328,6 +330,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
         swAuthenticationIndicator = view.findViewById(R.id.swAuthenticationIndicator);
 
         grpGravatars = view.findViewById(R.id.grpGravatars);
+        grpUnzip = view.findViewById(R.id.grpUnzip);
 
         List<StyleHelper.FontDescriptor> fonts = StyleHelper.getFonts(getContext());
 
@@ -1231,6 +1234,7 @@ public class FragmentOptionsDisplay extends FragmentBase implements SharedPrefer
         swFaviconsPartial.setText(getString(R.string.title_advanced_favicons_partial,
                 Helper.humanReadableByteCount(ContactInfo.FAVICON_READ_BYTES)));
         grpGravatars.setVisibility(ContactInfo.canGravatars() ? View.VISIBLE : View.GONE);
+        grpUnzip.setVisibility(Build.VERSION.SDK_INT < Build.VERSION_CODES.O ? View.GONE : View.VISIBLE);
         tvBimiUnverified.setVisibility(BuildConfig.DEBUG ? View.VISIBLE : View.GONE);
 
         PreferenceManager.getDefaultSharedPreferences(getContext()).registerOnSharedPreferenceChangeListener(this);

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

@@ -24,6 +24,7 @@ import static android.system.OsConstants.ENOSPC;
 import android.content.Context;
 import android.content.SharedPreferences;
 import android.net.Uri;
+import android.os.Build;
 import android.system.ErrnoException;
 import android.text.TextUtils;
 import android.util.Base64;
@@ -3385,7 +3386,7 @@ public class MessageHelper {
                         db.attachment().setWarning(local.id, Log.formatThrowable(ex));
                     }
 
-                else if (local.isCompressed()) {
+                else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O && local.isCompressed()) {
                     // https://commons.apache.org/proper/commons-compress/examples.html
                     SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
                     boolean unzip = prefs.getBoolean("unzip", true);

app/src/main/res/layout/fragment_options_display.xml

@@ -1795,6 +1795,12 @@
                     app:layout_constraintStart_toStartOf="parent"
                     app:layout_constraintTop_toBottomOf="@id/swAttachmentsAlt"
                     app:switchPadding="12dp" />
+
+                <androidx.constraintlayout.widget.Group
+                    android:id="@+id/grpUnzip"
+                    android:layout_width="0dp"
+                    android:layout_height="0dp"
+                    app:constraint_referenced_ids="swUnzip,tvUnzipHint" />
             </androidx.constraintlayout.widget.ConstraintLayout>
         </androidx.cardview.widget.CardView>