# cmux 0.64.21: Simulator Panes, Mosh Transport, Idle CPU Reclaimed

[ Changelog](https://cmux.com/docs/changelog)


August 2, 2026

### Native Simulator Panes

Run iPhone and iPad Simulators as first-class cmux panes, rendered crisply at real size, with their own commands and automation so an agent can drive the simulator next to the terminal that built it.

### Mosh for Remote Workspaces

Remote workspaces can use Mosh instead of plain SSH, so a laptop that sleeps, changes networks, or loses Wi-Fi picks the session back up instead of dropping it.

### Idle CPU and Memory Reclaimed

Leaked openThread loops that burned about 90% of cmux idle CPU are gone, hidden Ghostty renderers release their memory, workspace switching no longer freezes the renderer, and idle background agents hibernate under critical memory pressure.

### Navigation and Restore

Cmd+Shift+T reopens the last closed item, Cmd+\[ and Cmd+\] walk global workspace focus history, surfaces move between panes with automatic directional splits, and Dock panes, workspace IDs, and per-tab terminal zoom all survive a restart.

### cmux on iPhone (beta)

Stream Mac browser panes to the phone interactively, follow a chronological notification feed, launch agent workspaces from the task composer, and scroll terminals locally on screen-anchored render grids over a rebuilt peer-to-peer transport.

Added

-   Native iPhone and iPad Simulator panes, with their own commands and automation ([#7857](https://github.com/manaflow-ai/cmux/pull/7857))
-   First-class Mosh transport for remote workspaces ([#8442](https://github.com/manaflow-ai/cmux/pull/8442))
-   Workspace-wide terminal font zoom on Cmd+Ctrl+= / Cmd+Ctrl+- / Cmd+Ctrl+0 ([#8791](https://github.com/manaflow-ai/cmux/pull/8791)), and per-tab zoom now persists across restarts ([#8543](https://github.com/manaflow-ai/cmux/pull/8543))
-   Cmd+Shift+T reopens the last closed item ([#9132](https://github.com/manaflow-ai/cmux/pull/9132))
-   Cmd+\[ and Cmd+\] traverse global workspace focus history, and pane cycling becomes rebindable ([#9329](https://github.com/manaflow-ai/cmux/pull/9329)) -- thanks @azooz2003-bit! -- alongside a workspace-only focus history setting ([#8654](https://github.com/manaflow-ai/cmux/pull/8654))
-   Move active surfaces between panes with automatic directional splits ([#8764](https://github.com/manaflow-ai/cmux/pull/8764)); `goto_split:previous` and `goto_split:next` cycle through every pane with wrapping ([#2639](https://github.com/manaflow-ai/cmux/pull/2639)) -- thanks @mykmelez!
-   Dock panes persist across session restore ([#8690](https://github.com/manaflow-ai/cmux/pull/8690)), with full Dock surface runtime parity ([#8782](https://github.com/manaflow-ai/cmux/pull/8782))
-   Reopen closed workspaces with sticky repo identity ([#8841](https://github.com/manaflow-ai/cmux/pull/8841))
-   Target browser profiles from the CLI ([#8874](https://github.com/manaflow-ai/cmux/pull/8874)), and Command-clicked HTML files render in browser panes ([#9096](https://github.com/manaflow-ai/cmux/pull/9096))
-   Sidebar account and mobile pairing controls ([#8354](https://github.com/manaflow-ai/cmux/pull/8354)); sidebar metadata renders Markdown links ([#8663](https://github.com/manaflow-ai/cmux/pull/8663)) -- thanks @djova!
-   Notification feed read state is a leading swipe with mark-unread ([#8868](https://github.com/manaflow-ai/cmux/pull/8868)) -- thanks @azooz2003-bit!
-   Idle background agents hibernate under critical memory pressure even when routine Agent Hibernation is off ([#9090](https://github.com/manaflow-ai/cmux/pull/9090))
-   `cmux restore` runs without a shell ([#9265](https://github.com/manaflow-ai/cmux/pull/9265))
-   iOS (beta): stream Mac browser panes to the phone, interactive and pixel-perfect, with dialogs mirrored ([#8298](https://github.com/manaflow-ai/cmux/pull/8298)) -- thanks @azooz2003-bit!
-   iOS (beta): chronological notification feed ([#8210](https://github.com/manaflow-ai/cmux/pull/8210)) -- thanks @azooz2003-bit!
-   iOS (beta): launch agent workspaces straight from the task composer ([#7670](https://github.com/manaflow-ai/cmux/pull/7670))
-   iOS (beta): Tailscale connection method opt-in with QR-authorized pairing ([#9247](https://github.com/manaflow-ai/cmux/pull/9247)) -- thanks @azooz2003-bit!
-   iOS (beta): haptic feedback setting ([#8797](https://github.com/manaflow-ai/cmux/pull/8797)), Open Folders on Tap ([#8524](https://github.com/manaflow-ai/cmux/pull/8524)), unified animated toasts ([#8376](https://github.com/manaflow-ai/cmux/pull/8376)), and workspace identity customization ([#8636](https://github.com/manaflow-ai/cmux/pull/8636)) -- thanks @azooz2003-bit!

Changed

-   Workspace initial commands launch through your login shell ([#8801](https://github.com/manaflow-ai/cmux/pull/8801)) -- thanks @azooz2003-bit! -- and auto-resume uses the normal terminal shell ([#8837](https://github.com/manaflow-ai/cmux/pull/8837))
-   iOS (beta): the phone-to-Mac transport is rebuilt on one connectivity authority, with authenticated discovery, named disconnect reasons, and relay-credential rollover ([#9284](https://github.com/manaflow-ai/cmux/pull/9284), [#8840](https://github.com/manaflow-ai/cmux/pull/8840), [#8716](https://github.com/manaflow-ai/cmux/pull/8716), [#8494](https://github.com/manaflow-ai/cmux/pull/8494)) -- thanks @azooz2003-bit!
-   iOS (beta): terminal scrolling is local and smooth on screen-anchored render grids ([#8860](https://github.com/manaflow-ai/cmux/pull/8860)) -- thanks @azooz2003-bit!
-   iOS (beta): state sync v2 replaces the invalidate-and-refetch loop with per-record deltas ([#8284](https://github.com/manaflow-ai/cmux/pull/8284)) -- thanks @azooz2003-bit!
-   iOS (beta): onboarding is rebuilt around a live agent handoff ([#8418](https://github.com/manaflow-ai/cmux/pull/8418)), as a swipeable tour ([#9158](https://github.com/manaflow-ai/cmux/pull/9158)) with a Game of Life backdrop on every page ([#8880](https://github.com/manaflow-ai/cmux/pull/8880)) -- thanks @azooz2003-bit!
-   iOS (beta): removing a Mac from a phone hides it for that phone only, instead of deleting it everywhere ([#8760](https://github.com/manaflow-ai/cmux/pull/8760), [#8778](https://github.com/manaflow-ai/cmux/pull/8778)) -- thanks @azooz2003-bit!

Fixed

-   Fix leaked `openThread` loops burning ~90% of cmux idle CPU ([#8851](https://github.com/manaflow-ai/cmux/pull/8851))
-   Fix workspace-switch renderer freezes ([#8793](https://github.com/manaflow-ai/cmux/pull/8793)), reclaim hidden Ghostty renderer memory ([#8998](https://github.com/manaflow-ai/cmux/pull/8998)), and fix the Vault sidebar beachball at large session counts ([#8680](https://github.com/manaflow-ai/cmux/pull/8680))
-   Fix Vim Mode cursor and selection rendering ([#8995](https://github.com/manaflow-ai/cmux/pull/8995))
-   Fix TextBox IME composition rendering ([#8688](https://github.com/manaflow-ai/cmux/pull/8688))
-   Fix zsh prompt wrap spacer lines by letting Ghostty own prompt layout ([#8964](https://github.com/manaflow-ai/cmux/pull/8964))
-   Fix Settings and main window zombies under AeroSpace ([#8513](https://github.com/manaflow-ai/cmux/pull/8513)) -- thanks @fml09!
-   Fix a Debug-build crash on macOS 26.5 from non-finite sidebar divider coordinates ([#9156](https://github.com/manaflow-ai/cmux/pull/9156)) -- thanks @oscarbrey!
-   Fix Mermaid diagrams double-scaling under viewer zoom ([#8914](https://github.com/manaflow-ai/cmux/pull/8914)), restore the focused-read indicator after a surface-scoped mark-read ([#8927](https://github.com/manaflow-ai/cmux/pull/8927)), keep Pi launch arguments when resuming a restored session ([#8912](https://github.com/manaflow-ai/cmux/pull/8912)), and import appearance at Settings store init instead of live-applying it ([#8913](https://github.com/manaflow-ai/cmux/pull/8913)) -- thanks @ejc3!
-   Notify only after the Pi agent settles ([#8574](https://github.com/manaflow-ai/cmux/pull/8574)) -- thanks @mrohan-sq!
-   Tear down remote daemon PTY sessions once ([#8643](https://github.com/manaflow-ai/cmux/pull/8643)) -- thanks @ejc3! -- and support `respawn-pane` in the Go relay tmux compatibility layer ([#8660](https://github.com/manaflow-ai/cmux/pull/8660)) -- thanks @bencollins2!
-   Exclude `.attrib` from watched filesystem events ([#8659](https://github.com/manaflow-ai/cmux/pull/8659)) -- thanks @varomorf!
-   Preserve surface IDs in workstream events ([#8703](https://github.com/manaflow-ai/cmux/pull/8703)) -- thanks @revanthreddy-hai!
-   Stop the sidebar PR poller from re-downloading every repo's full PR list on each poll ([#8521](https://github.com/manaflow-ai/cmux/pull/8521)) -- thanks @joshfree!
-   Restore Codex ([#9370](https://github.com/manaflow-ai/cmux/pull/9370)), Kimi Code ([#8584](https://github.com/manaflow-ai/cmux/pull/8584)), Grok ([#9382](https://github.com/manaflow-ai/cmux/pull/9382)), and Pi ([#9399](https://github.com/manaflow-ai/cmux/pull/9399)) sessions across relaunch, and stop duplicate agent resumes ([#8619](https://github.com/manaflow-ai/cmux/pull/8619))
-   ssh-tmux: fix focus after single-pane promotion ([#9020](https://github.com/manaflow-ai/cmux/pull/9020)), named-key encoding for the remote `TERM` ([#9273](https://github.com/manaflow-ai/cmux/pull/9273)), and terminal replies leaking into reattached panes ([#9272](https://github.com/manaflow-ai/cmux/pull/9272)); fix workspace shortcuts from hosted tmux terminals ([#8621](https://github.com/manaflow-ai/cmux/pull/8621))
-   Fix SSH relay deadlock after app restart ([#9105](https://github.com/manaflow-ai/cmux/pull/9105)), stale SSH workspace connection status ([#9085](https://github.com/manaflow-ai/cmux/pull/9085)), remote PTY `PATH` inherited from cmuxd ([#8677](https://github.com/manaflow-ai/cmux/pull/8677)), and login-shell resolution before terminal spawn ([#8681](https://github.com/manaflow-ai/cmux/pull/8681))
-   Fix sidebar reopen cutoff render ([#8626](https://github.com/manaflow-ai/cmux/pull/8626)), row clipping during height-changing reorder ([#9189](https://github.com/manaflow-ai/cmux/pull/9189)), idle layout livelock ([#8532](https://github.com/manaflow-ai/cmux/pull/8532)), and status URL clicks ([#8528](https://github.com/manaflow-ai/cmux/pull/8528))
-   Fix Dock paste routing to the selected terminal ([#9112](https://github.com/manaflow-ai/cmux/pull/9112)), Dock terminal working-directory inheritance ([#8691](https://github.com/manaflow-ai/cmux/pull/8691)), and Cmd-click link opening in Dock terminals ([#8594](https://github.com/manaflow-ai/cmux/pull/8594))
-   Browser: fix navigation for terminal-wrapped URL pastes ([#8601](https://github.com/manaflow-ai/cmux/pull/8601)), automation recovery after load failures ([#8548](https://github.com/manaflow-ai/cmux/pull/8548)), partial blank screenshots ([#9281](https://github.com/manaflow-ai/cmux/pull/9281)), and blurred Google Sheets canvas rendering ([#8697](https://github.com/manaflow-ai/cmux/pull/8697))
-   Fix inline code escaping in the Markdown viewer ([#9274](https://github.com/manaflow-ai/cmux/pull/9274)) and composer attachment thumbnail re-rasterization ([#8817](https://github.com/manaflow-ai/cmux/pull/8817))
-   Fix renderer presentation for background-created surfaces ([#8540](https://github.com/manaflow-ai/cmux/pull/8540)) and stale semantic prompts duplicating inline TUI frames ([#9275](https://github.com/manaflow-ai/cmux/pull/9275))
-   Fix workspace group anchor numbering ([#9176](https://github.com/manaflow-ai/cmux/pull/9176)); closing a group's anchor keeps the group instead of scattering its members to the root ([#8925](https://github.com/manaflow-ai/cmux/pull/8925))
-   Preserve workspace IDs across session restore ([#8695](https://github.com/manaflow-ai/cmux/pull/8695)) and restored resume workspace titles ([#8687](https://github.com/manaflow-ai/cmux/pull/8687)); fit same-display restored windows to visible bounds ([#8675](https://github.com/manaflow-ai/cmux/pull/8675))
-   Fix a `DispatchWorkItem` chain stack overflow ([#8615](https://github.com/manaflow-ai/cmux/pull/8615)) and subprocess pipe descriptor leaks ([#9187](https://github.com/manaflow-ai/cmux/pull/9187))
-   iOS (beta): preserve terminal input ordering under fast typing ([#8682](https://github.com/manaflow-ai/cmux/pull/8682)), scroll position across mid-stream verified replays ([#9032](https://github.com/manaflow-ai/cmux/pull/9032)), and keyboard focus after the photo picker ([#9287](https://github.com/manaflow-ai/cmux/pull/9287)) -- thanks @azooz2003-bit!
-   iOS (beta): fix a startup crash from sentry-init racing environ mutation ([#9238](https://github.com/manaflow-ai/cmux/pull/9238)) and TestFlight crash paths ([#9034](https://github.com/manaflow-ai/cmux/pull/9034))
-   iOS (beta): fix workspace-list scroll stutter from live updates ([#9139](https://github.com/manaflow-ai/cmux/pull/9139)), and make the notification feed scroll fast with thousands of items ([#9141](https://github.com/manaflow-ai/cmux/pull/9141)) -- thanks @azooz2003-bit!

Contributors

[![austinywang](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Faustinywang.png%3Fsize%3D48&w=48&q=75)austinywang](https://github.com/austinywang) [![azooz2003-bit](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Fazooz2003-bit.png%3Fsize%3D48&w=48&q=75)azooz2003-bit](https://github.com/azooz2003-bit) [![bencollins2](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Fbencollins2.png%3Fsize%3D48&w=48&q=75)bencollins2](https://github.com/bencollins2) [![djova](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Fdjova.png%3Fsize%3D48&w=48&q=75)djova](https://github.com/djova) [![ejc3](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Fejc3.png%3Fsize%3D48&w=48&q=75)ejc3](https://github.com/ejc3) [![fml09](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Ffml09.png%3Fsize%3D48&w=48&q=75)fml09](https://github.com/fml09) [![joshfree](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Fjoshfree.png%3Fsize%3D48&w=48&q=75)joshfree](https://github.com/joshfree) [![lawrencecchen](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Flawrencecchen.png%3Fsize%3D48&w=48&q=75)lawrencecchen](https://github.com/lawrencecchen) [![mrohan-sq](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Fmrohan-sq.png%3Fsize%3D48&w=48&q=75)mrohan-sq](https://github.com/mrohan-sq) [![mykmelez](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Fmykmelez.png%3Fsize%3D48&w=48&q=75)mykmelez](https://github.com/mykmelez) [![oscarbrey](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Foscarbrey.png%3Fsize%3D48&w=48&q=75)oscarbrey](https://github.com/oscarbrey) [![revanthreddy-hai](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Frevanthreddy-hai.png%3Fsize%3D48&w=48&q=75)revanthreddy-hai](https://github.com/revanthreddy-hai) [![varomorf](https://cmux.com/_next/image?url=https%3A%2F%2Fgithub.com%2Fvaromorf.png%3Fsize%3D48&w=48&q=75)varomorf](https://github.com/varomorf)

[ cmux 0.64.20](https://cmux.com/docs/changelog/0.64.20) [cmux 0.64.22 ](https://cmux.com/docs/changelog/0.64.22)

Canonical: https://cmux.com/docs/changelog/0.64.21

Documentation index: https://cmux.com/llms.txt