Every Confirmed Feature in macOS Tahoe 26.4 Beta

Apple’s macOS Tahoe 26.4 beta, seeded to developers in February 2026, adds a granular battery charge limit slider, restores the Safari compact tab bar that vanished when Liquid Glass launched, and begins showing Rosetta 2 deprecation warnings every time you open an Intel-only app. Those are the headline changes. The complication: several of these features hide behind sub-menus, one requires Apple Silicon hardware, and the beta ships with a known bug that mounts HFS+ volumes as read-only. This walkthrough covers every confirmed change, where to find each setting, and what to watch for before you install.

The battery charge limit alone makes 26.4 worth paying attention to. Previous macOS versions offered only Optimized Battery Charging, which relied on machine learning to decide when to cap the charge. The new slider in macOS Tahoe 26.4 gives you a hard ceiling from 80% to 100% in 5% increments. Set it to 85%, and your MacBook stops charging at 85% every single time. Apple notes the system will occasionally charge to 100% to maintain accurate battery state-of-charge estimates, but the behavior is otherwise absolute. For a deeper look at why that distinction matters, the dedicated battery slider walkthrough breaks it down step by step.

Safari’s compact tab bar is the other restoration that long-time Mac users will notice immediately. When macOS Tahoe shipped in September 2025, Apple removed the compact layout because it conflicted with the Liquid Glass visual overhaul. Seven months later, it returns. Enabling it merges the address bar and tab strip into a single row, reclaiming vertical space on smaller displays like the MacBook Air 13-inch.

The Battery Charge Limit Slider Gives You a Hard Cap

Open System Settings, then click Battery. Next to the Charging label, click the small info icon (the circle with an “i” inside it). A new panel appears with a slider labeled Charge Limit. Drag the slider to your preferred maximum. The range spans 80% to 100% in 5% increments.

This is a hard cap, not an adaptive suggestion. Optimized Battery Charging, which still exists as a separate toggle, learns your routine and delays topping off to 100% until you typically unplug. The new slider overrides that intelligence with a fixed ceiling. Both can run simultaneously: you might set the slider to 90% and leave Optimized Battery Charging enabled, so the system aims for 90% but may hold at 80% until close to your usual departure time.

The slider works only on Apple Silicon Macs. Intel Macs do not gain this feature. There is also a new Shortcuts action called Set Battery Charge Limit that lets you automate the ceiling. You could build a shortcut that lowers the limit to 80% when your Work Focus activates (because you are plugged in at a desk all day) and raises it to 95% when you trigger a Travel Focus before heading to the airport. Tying battery management to Focus modes turns a manual slider into something genuinely hands-free.

Safari Compact Tab Bar Returns After Seven Months

Open Safari, click Safari in the menu bar, then click Settings. Select the Tabs pane. Two options appear: Separate and Compact. Choose Compact.

Separate is the default Liquid Glass layout where the address bar occupies its own row above the tab strip. Compact collapses both into one row: each tab becomes a pill that doubles as the address field when selected. The visual difference is roughly 36 pixels of vertical space recovered. That sounds minor on a 27-inch iMac display, but on a 13-inch MacBook Air, where every visible line of a webpage counts, the difference is real.

The compact layout is also back in iPadOS 26.4, so the change applies across both platforms. One friction point worth noting: tab favicons in compact mode are smaller and harder to distinguish when you have more than a dozen tabs open. The trade-off is screen real estate versus tab identification at a glance.

macOS Tahoe 26.4 At-A-Glance

Rosetta 2 Warnings Signal the End of Intel App Support

Starting in macOS 26.4, launching an Intel-only (x86_64) application triggers a dialog warning that the app needs to be updated for Apple Silicon. The dialog includes a link to an Apple support page explaining how to identify and update Intel apps on your Mac.

The deprecation timeline is clear. macOS 27, expected in September 2026, drops support for Intel-based Macs entirely. Rosetta 2 remains available on Apple Silicon Macs running macOS 27, so translated Intel apps still function for one more cycle. In macOS 28, expected in 2027, Apple removes Rosetta 2 altogether, with limited exceptions for Linux virtual machines and legacy game compatibility layers. Developers have had over five years since the Apple Silicon transition began in November 2020 to ship universal binaries.

For daily Mac use, the practical impact is that apps running through Rosetta 2 translation carry measurable overhead: higher memory consumption, slower launch times, and no access to Apple Silicon-specific optimizations. The performance troubleshooting guide covers how to identify which apps are still running translated and what to do when native versions are not yet available.

RCS Encryption Arrives in Messages, With a Catch

The Messages app in macOS Tahoe 26.4 gains end-to-end encryption for RCS conversations. This uses RCS Universal Profile 3.0, up from version 2.4, which adds the encryption layer that RCS has lacked since Apple adopted the protocol.

The catch: in the 26.4 beta, encrypted RCS works only between iPhones. Cross-platform encrypted RCS (iPhone to Android) is not active yet. Apple has confirmed that full cross-platform E2E encrypted RCS will ship “in a future iOS 26 software update,” meaning a later point release, not 26.4 itself. When that broader rollout arrives, it will also enable editing and recalling sent RCS messages, plus inline reply threading.

Bug Fixes and Known Beta Issues Worth Watching

The window corner radius bug that shipped with the original macOS Tahoe release is finally fixed. Since September 2025, the window resize pointer did not follow the rounded corner shape of Liquid Glass windows, making it difficult to grab the corner for resizing. The macOS 26.3 release notes claimed to fix this, but the bug persisted. The 26.4 beta actually resolves it.

Known Issues in the 26.4 Beta

HFS+ volumes mount as read-only. Apple accidentally shipped a debug build of the fsck_hfs binary, which causes HFS+ formatted drives to mount without write access. Your data is not corrupted. The drives function normally on other Macs running earlier macOS versions. The workaround is to mount manually via Terminal:

diskutil mount /dev/diskXsY (replace X and Y with your actual disk and partition numbers).

DMG disk images may fail to mount through Finder. Use hdiutil attach /path/to/image.dmg in Terminal as a workaround.

12-hour time format displays noon as 00:00 PM instead of 12:00 PM. This is a display bug in the menu bar clock and calendar apps. Apple acknowledges the issue.

What Is Not in 26.4 Yet

New emoji characters are expected for 2026 but have not appeared in the 26.4 beta builds so far. They may arrive in a later beta seed. Larger Siri and Apple Intelligence upgrades that Apple previewed at WWDC 2025 are also absent, reportedly delayed to a separate macOS update later this year.

Accessibility and Clarity

The battery charge limit slider uses a standard macOS slider control, fully accessible through VoiceOver. VoiceOver announces the current percentage and allows adjustment with arrow keys. The info icon that reveals the slider panel is labeled for assistive technology, so screen reader users can locate it without relying on visual cues.

The Rosetta 2 deprecation dialog includes both a text explanation and a clickable link. The warning does not depend on color alone to communicate urgency. Screen readers announce the dialog content automatically when it appears.

Safari’s compact versus separate tab layout can be toggled entirely through keyboard navigation: Safari menu, Settings, then arrow keys to the Tabs pane. Both layouts maintain the same keyboard shortcut mappings for tab switching (Command-Shift-bracket keys), so muscle memory transfers between modes without relearning.

Quick-Action Checklist

1. Open System Settings, click Battery, click the info icon next to Charging, and drag the Charge Limit slider to your preferred maximum between 80% and 100%.
2. Open Safari Settings, select the Tabs pane, and switch from Separate to Compact to recover vertical screen space.
3. Launch any Intel-only app to verify whether the Rosetta 2 deprecation warning appears, then check for a native update from the developer.
4. Open the Shortcuts app and search for the Battery Charge Limit action to build automation tied to your Focus modes.
5. Test window corner resizing on any Liquid Glass window to confirm the pointer now follows the rounded shape.
6. Avoid formatting HFS+ drives from this beta. Use diskutil mount in Terminal as a workaround for read-only HFS+ volumes.