--- title: "PSPDFKit 4 iOS Migration Guide - Seamless Upgrade Instructions" canonical_url: "https://www.nutrient.io/guides/ios/migration-guides/pspdfkit-4-migration-guide/" md_url: "https://www.nutrient.io/guides/ios/migration-guides/pspdfkit-4-migration-guide.md" last_updated: "2026-06-08T09:14:14.405Z" description: "Migration guide for Nutrient iOS SDK version 4 with breaking changes, API updates, and upgrade instructions." --- PSPDFKit 4 for iOS is a major new release and includes many new features and a few breaking changes. It’s the first release that was rethought from the ground up with iOS 8 in mind (backward compatible to iOS 7), and we were able to redesign many aspects that were suboptimal in PSPDFKit 3 for iOS due to the iOS 5/6 requirement. ### Requirements Starting with PSPDFKit 4.0, you’ll need iOS 7.0 upward and Xcode 6.0 (SDK 8) to compile. Your apps can be written in Objective-C or Swift. We also require `UIViewControllerBasedStatusBarAppearance` to be set to `YES`. This is the default behavior for any app beginning with iOS 7. However, Apple lets you customize this behavior. PSPDFKit v3 supported both modes of operation, but since the view controller-based status bar appearance clearly is the future, we’ll focus on that. ### License The PSPDFKit 4 demo now requires a license both for the demo and for the licensed versions. This change was made in response to people having issues entering the license key. Use our website to obtain a demo key while you’re evaluating. If you’re just testing PSPDFKit Catalog, no custom keys are required. ### PSPDFDocument The document model in 4.0 is now immutable for data sources. This allows faster internal code handling. If you need to change your data sources for your document, create a new document using the [`documentByAppendingObjects:`](https://www.nutrient.io/api/ios/documentation/pspdfkit/document/appendingdataproviders(_:)) helper that will accept `NSString`, `NSData`, or a `CGDataProviderRef`. ### PSPDFViewController We modernized the view controller API and removed several properties that were no longer in line with iOS 7: `tintColor`, `shouldTintPopovers`, `transparentHUD`, and `minLeft/RightToolbarWidth`. Use `UIAppearance` to customize colors and tint throughout PSPDFKit. See our [appearance styling](https://www.nutrient.io/../../customizing-the-interface/appearance-styling) guide for details. Most properties, including the [`overrideClass:withClass:`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfconfigurationbuilder/overrideclass(_:with:)) method, have been moved to the new [`PSPDFConfiguration`](https://github.com/PSPDFKit/PSPDFKit-Demo/wiki/PSPDFConfiguration) object, which better defines when configuration changes should be done and also allows you to archive/export complete configuration sets. See PSPDFKit Catalog for examples of how to use [`PSPDFConfiguration`](https://github.com/PSPDFKit/PSPDFKit-Demo/wiki/PSPDFConfiguration). The `setUpdateSettingsForRotationBlock:` method has been replaced with the more generic `setUpdateSettingsForBoundsChangeBlock:`. Ask the [`PSPDFViewController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfviewcontroller) to get the current interface rotation. ### Status Bar The status bar is now managed by view controllers, and as such, by your `UINavigationController` subclass. As a result, we completely deleted `PSPDFStatusBarStyle` and the matching `statusBarStyleSetting` property. This is now controlled by the navigation bar style set in your `UINavigationController`. We added a new property, [`shouldHideStatusBar`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfconfiguration/shouldhidestatusbar), to the [`PSPDFViewController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfviewcontroller); this property controls the status bar appearance globally in all used view controllers as a convenience method for you. ### Annotation Toolbar The old [`PSPDFAnnotationToolbar`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/annotationtoolbar) has been removed in favor of the more modern and flexible [`PSPDFFlexibleAnnotationToolbar`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/flexibletoolbar) that we introduced in PSPDFKit 3.6 for iOS. To simplify things, we renamed this new modern toolbar to [`PSPDFAnnotationToolbar`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/annotationtoolbar). You’ll have to update your code if you used a subclass of the old class. ### Digital Signing Architecture We updated the signing architecture to allow signing using PKI hardware and to allow removing signatures. Many internal classes have been updated and improved. ### Data Model We made various changes to the way annotations and other data are now archived via `NSKeyedArchiver`. PSPDFKit is downward compatible and can read its own format starting with version 3.0. Make sure older installations don’t try to parse the PSPDFKit 4 data format, as they’ll lose certain information from the PSPDFKit 4 data format. ### Various Other Changes `PSPDFURLConnection` has been completely removed in favor of `NSURLSession`. If your code was using this internal class, update your calls or use something like `AFNetworking` instead. `PSPDFIndexSetFromArray()` has been replaced by a category in PSPDFKit Catalog. See `NSArray+PSCIndexSet.h`. Many classes now work independently of [`PSPDFViewController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfviewcontroller). A new [`PSPDFPresentationContext`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/presentationcontext) protocol has been introduced; it defines a subset of [`PSPDFViewController`](https://www.nutrient.io/api/ios/documentation/pspdfkitui/pdfviewcontroller) to make these internal components reusable. --- ## Related pages - [14 9 Migration Guide](/guides/ios/migration-guides/14-9-migration-guide.md) - [14 2 Migration Guide](/guides/ios/migration-guides/14-2-migration-guide.md) - [Migrate to electronic signatures](/guides/ios/migration-guides/migrating-to-electronic-signatures.md) - [Migrating To Advanced Digital Signatures Api](/guides/ios/migration-guides/migrating-to-advanced-digital-signatures-api.md) - [Pspdfkit 10 3 Migration Guide](/guides/ios/migration-guides/pspdfkit-10-3-migration-guide.md) - [Pspdfkit 10 4 Migration Guide](/guides/ios/migration-guides/pspdfkit-10-4-migration-guide.md) - [Migrating From Apple Pdfkit](/guides/ios/migration-guides/migrating-from-apple-pdfkit.md) - [Pspdfkit 11 3 Migration Guide](/guides/ios/migration-guides/pspdfkit-11-3-migration-guide.md) - [Pspdfkit 10 Migration Guide](/guides/ios/migration-guides/pspdfkit-10-migration-guide.md) - [Pspdfkit 12 2 Migration Guide](/guides/ios/migration-guides/pspdfkit-12-2-migration-guide.md) - [Pspdfkit 11 5 Migration Guide](/guides/ios/migration-guides/pspdfkit-11-5-migration-guide.md) - [Pspdfkit 13 3 Migration Guide](/guides/ios/migration-guides/pspdfkit-13-3-migration-guide.md) - [Pspdfkit 13 Migration Guide](/guides/ios/migration-guides/pspdfkit-13-migration-guide.md) - [Pspdfkit 12 3 Migration Guide](/guides/ios/migration-guides/pspdfkit-12-3-migration-guide.md) - [Pspdfkit 3 Migration Guide](/guides/ios/migration-guides/pspdfkit-3-migration-guide.md) - [Pspdfkit 12 Migration Guide](/guides/ios/migration-guides/pspdfkit-12-migration-guide.md) - [Pspdfkit 5 Migration Guide](/guides/ios/migration-guides/pspdfkit-5-migration-guide.md) - [Pspdfkit 6 5 Migration Guide](/guides/ios/migration-guides/pspdfkit-6-5-migration-guide.md) - [Pspdfkit 6 Migration Guide](/guides/ios/migration-guides/pspdfkit-6-migration-guide.md) - [Pspdfkit 11 4 Migration Guide](/guides/ios/migration-guides/pspdfkit-11-4-migration-guide.md) - [Pspdfkit 7 6 Migration Guide](/guides/ios/migration-guides/pspdfkit-7-6-migration-guide.md) - [Pspdfkit 9 2 Migration Guide](/guides/ios/migration-guides/pspdfkit-9-2-migration-guide.md) - [Pspdfkit 9 4 Migration Guide](/guides/ios/migration-guides/pspdfkit-9-4-migration-guide.md) - [Upgrading](/guides/ios/getting-started/upgrading.md) - [Pspdfkit 9 5 Migration Guide](/guides/ios/migration-guides/pspdfkit-9-5-migration-guide.md) - [Pspdfkit 9 3 Migration Guide](/guides/ios/migration-guides/pspdfkit-9-3-migration-guide.md) - [PSPDFKit 8 migration guide for iOS developers](/guides/ios/migration-guides/pspdfkit-8-migration-guide.md) - [Pspdfkit 9 Migration Guide](/guides/ios/migration-guides/pspdfkit-9-migration-guide.md) - [Migrate to PSPDFKit 7 with ease](/guides/ios/migration-guides/pspdfkit-7-migration-guide.md)