Serial Port Utility 6.6.6

Features

• The App Store build now takes a license key bought on the website: A perpetual license kept unlocking Pro in the App Store build, but there was nowhere to type its key in — a new Mac was a dead end short of switching to the direct download. The subscription dialog now has an Enter License Key entry that opens the same license window as the direct build (minus the buy button, per App Store rules); a key bound to an Alithon account still activates on sign-in and releases on sign-out; and an installed key is checked with the license server at startup for renewals and disabling, exactly as in the direct build
• Parameter changes reach an open port at once: Editing the baud rate, framing or flow control in the quick settings did nothing to an open serial port — the value was stored for the next open, the status bar kept showing what the port actually ran, and nothing on screen said so. It was the only parameter path in the application that did not take effect immediately (switching ports reopens, an RFC 2217 client pushes SET-BAUDRATE, Live Console reopened). The change now lands on the open port in place, without a close-and-reopen — a reopen drops DTR and resets most dev boards, which is not what "set the baud rate" asked for. A value the driver refuses rolls the accepted ones back too, so the port never runs a mixture; a transfer in progress refuses the change and says why. Live Console and the headless CLI take the same path: on failure the port stays open with its previous parameters instead of disconnecting

Interface

• Stop bits join the quick-settings drawer: The connection group's default-hidden fields used to be Data Bits and Parity only; Stop Bits (nearly always 1) now stays off the panel out of the box too, still editable in the settings dialog. Anyone who has configured that group's visible fields is untouched
• The Microsoft Store build puts an icon on the desktop: The Store install used to reach no further than the Start menu. Installing now creates a desktop shortcut (on Windows 10 build 19645 and later; older systems install as before, just without it)

Fixes

• The Help menu offered the subscription twice in the App Store build: "Subscribe to SPU Pro…" and "SPU Pro Subscription…" opened the same dialog, and read identically while unsubscribed. One entry remains, its label following the subscription state
• The App Store build called a legacy license a subscription: A perpetual-license holder was told twice over that they had subscribed: the registration button read "Subscribed" and the Help menu "SPU Pro Subscription…" — a subscription they never took out. Both now follow where the entitlement actually comes from — "Licensed" and "SPU Pro License…" — the way the About box already says "SPU Pro (Legacy License)"
• Leaving serial for a network target never stopped the old session: Switching an open serial port to a network target (Live Relay, RFC 2217, TCP/UDP) in the inline editor closed only the port handle; the session state stayed "running", so the toolbar kept Start greyed and Stop armed while nothing had dialled the new target, and only a manual Stop/Start cleared it. The settings dialog had the same hole one layer down: a mode change adopted the new model without ending the old session, leaking the old transport where Stop could no longer reach it. Both paths now stop the old session first
• A long PAUSE ate memory, and resuming froze the window: PAUSE diverted every incoming byte into an unbounded buffer — an afternoon of pause on a busy link was an unbounded allocation — and resuming replayed the whole backlog as one giant frame, one decode and one insertion that froze the window for seconds. The pause buffer is now capped at the display buffer size, dropping the oldest bytes so what you un-pause to is the newest; the Rx counter counts at arrival, so the wire statistics never shrink to what survived the cap; and the resume replays in 64 KB frames under a 256 KB-per-tick rendering budget, keeping the window responsive throughout
• An open find bar pinned the interface under streaming traffic: With the find bar open, every 20 ms display tick that carried data re-scanned the entire receive document — find, filter and highlight each time — and a large document under continuous traffic pinned the GUI. Traffic-driven rescans now coalesce to at most one per 250 ms; typing a keyword, F3, the option boxes, a send echo, stop and clear still refresh at once
• The license key no longer reaches the log: Checking a license used to print the raw key, its hashes and the signature to standard error along with the rest of the debug output — on macOS, that is the system log. Debug output is now off by default and grouped by module, to be switched on only when something needs looking into; the license lines are gone for good. Start-up also loses the warning about a missing font family, and the 70–80 ms font-alias scan behind it