diff --git a/README.md b/README.md
index 8393359..d12162e 100644
--- a/README.md
+++ b/README.md
@@ -155,7 +155,8 @@ Now you can install `droidfs.apk` on your device.
 Thanks to these open source projects that DroidFS uses:
 
 ### Modified code:
-- [gocryptfs](https://github.com/rfjakob/gocryptfs) to encrypt your data
+- [libgocryptfs](https://forge.chapril.org/hardcoresushi/libgocryptfs) (forked from [gocryptfs](https://github.com/rfjakob/gocryptfs)) to encrypt your data
+- [libpdfviewer](https://forge.chapril.org/hardcoresushi/libpdfviewer) (forked from [PdfViewer](https://github.com/GrapheneOS/PdfViewer)) to open PDF files
 - [DoubleTapPlayerView](https://github.com/vkay94/DoubleTapPlayerView) to add double-click controls to the video player
 ### Borrowed code:
 - [MaterialFiles](https://github.com/zhanghai/MaterialFiles) for kotlin natural sorting implementation
diff --git a/app/build.gradle b/app/build.gradle
index d08d589..46e0ec5 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -15,8 +15,8 @@ android {
         minSdkVersion 21
         //noinspection ExpiredTargetSdkVersion
         targetSdkVersion 29
-        versionCode 24
-        versionName "1.9.0"
+        versionCode 25
+        versionName "1.9.1"
 
         ndk {
             abiFilters "x86", "x86_64", "armeabi-v7a", "arm64-v8a"
diff --git a/app/src/main/java/sushi/hardcore/droidfs/file_viewers/PdfViewer.kt b/app/src/main/java/sushi/hardcore/droidfs/file_viewers/PdfViewer.kt
index 73e5af3..9da796a 100644
--- a/app/src/main/java/sushi/hardcore/droidfs/file_viewers/PdfViewer.kt
+++ b/app/src/main/java/sushi/hardcore/droidfs/file_viewers/PdfViewer.kt
@@ -2,7 +2,7 @@ package sushi.hardcore.droidfs.file_viewers
 
 import android.view.Menu
 import android.view.MenuItem
-import org.grapheneos.pdfviewer.PdfViewer
+import app.grapheneos.pdfviewer.PdfViewer
 import java.io.ByteArrayInputStream
 import java.io.File
 
diff --git a/libpdfviewer b/libpdfviewer
index 0f31234..8fe8b2f 160000
--- a/libpdfviewer
+++ b/libpdfviewer
@@ -1 +1 @@
-Subproject commit 0f312347ddcff4aab5edd7d7fdb6837c67584d56
+Subproject commit 8fe8b2f4b3aecd3ad210478fd99df9f260503db8