Today we are very excited to introduce version 6.10.3 of PDFTron's Android PDF SDK. This release includes two new library packages for out-of-the-box real-time document collaboration, and more. This blog post will go through the major changes in 6.10.3. For the full list of changes, please head over to our changelog for PDFTron 6.10.3 for Android.

linkTry it out

Try out the Web Collaboration Demo together with the new Android Collaboration Demo.


In your app module's build.gradle file (usually app/build.gradle), set the minSdkVersion to 21+ and enable compatibility for Java 8 features. Then, add the dependency for PDFTron's collaboration package:

android {
    defaultConfig {
        minSdkVersion 21
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8

dependencies {
    implementation "com.pdftron:collab:6.10.3"

For a more detailed integration tutorial, check out our integration guides.

linkAnnotation syncing

With this out-of-the-box collaboration package, you will no longer need to worry about extracting client side annotations from the document or importing remote annotations to the document. We do all the hard work for you! All you need to do is to implement an interface that: notifies the client about server changes, and sends client-side changes to the server. PDFTron will update the viewer and provide the proper user permissions for each annotation in the UI - only the annotation creator will be able to edit/delete it and any collaborator can comment on it.

The annotations appearing on the document in real time are managed through a separate XFDF format, while the original version of the document is preserved on the server. Note that the client downloads the original untouched document at the start of the collaboration session.

You can learn more about annotation syncing here:

linkAnnotation reply

The UI for replying to annotations is packaged with the collaboration library, and users will be able to add, edit, or delete their annotation replies directly. The reply UI is also fully customizable, allowing you to change the theme to match the desired look for your app.

You can learn more about customizing the reply UI here:


Notifications are a helpful visual cue to notify users of any conversations that are happening in real-time. Notification indicators in the viewer and the annotation list let users know that there are unread annotation replies:

ViewerAnnotation list

linkWebViewer Server compatibility

If you are hosting annotations in your WebViewer Server, PDFTron also provides a utility add-on package that will provide out-of-the-box support for real-time document collaboration with your WebViewer Server.

See a detailed tutorial here:

linkAnd more...

Check out our detailed tutorial blog post on How to Build an Android App for Document Collaboration with Firebase.

For a full list of changes, please see the changelog for PDFTron 6.10.3 for Android.

We hope you like these changes and any feedback is greatly appreciated. Please don't hesitate to contact us if you have any questions or suggestions. We also have many exciting new features planned for the coming weeks and months. Stay tuned...