These release notes apply to every platform build. Download details stay in the platform picker.
Features
Local echo: Terminal passthrough now echoes what you type in the receive view, so a device that never echoes back — common on embedded targets — no longer leaves you typing blind. It is separate from Display Send, which shows and logs whole frames from the send box: local echo renders keystrokes in place, in typing order, and keeps them out of the log. Off by default, since a device that does echo would otherwise double every character
Indicator lights toggle: The quick-settings panel can now hide the TX/RX and control-line indicators and give the space back to the data views
Cloud Console live channel: The cloud console now carries commands and status over a WebSocket instead of polling, removing the poll-interval delay. A backend that does not advertise the gateway keeps working on the previous HTTP polling path
Interface
The quick-settings bar drags narrower: Its minimum width used to follow the longest port name, the longest combo entry and the widest label all at once, pinning the bar near 300 pixels. Long combo entries now elide in place — the popup still shows them in full — and the shared label column stops growing, so the bar goes as narrow as you need it
Consistent settings terminology: Options… is now Settings… in the main window and the multi-port dialog, the terminal's connection, receive and send settings read consistently, and the settings panel's Options group is named Log Behavior after what it actually holds
Fixes
Misaligned columns from a missing monospace font: The receive and send views name Monaco, which does not exist outside macOS — only Windows' Consolas was substituted before — so those views fell back to a proportional face and the HEX and timestamp columns drifted out of line. Both families now substitute to the system monospace font when they are missing
Online services missing from Microsoft Store builds: MSIX packaging compiled out account sign-in, cloud sync and the cloud console entirely, so the Store build shipped without them. It now matches the direct download
Version archive
Previous releases
Choose a platform to review older builds and their release notes.
X/YMODEM file transfer: Send and receive files over an established serial, TCP or RFC 2217 connection with XMODEM, XMODEM-CRC, XMODEM-1K, YMODEM and YMODEM-G. Protocol traffic is isolated from ordinary terminal data, while a non-modal progress bar reports the file, progress, rate, ETA and retry count. TCP servers can pin a selected client, so remote firmware updates no longer require another terminal application
Single-connection RFC 2217 remote serial: RFC 2217 is now available directly in the port list for connecting to Moxa NPort, ser2net or another Serial Port Utility and setting remote baud rate, data bits, parity, stop bits, flow control and DTR/RTS in the same connection. The device server's existing configuration is preserved by default; parameters are sent only after the user explicitly takes control. Peers without RFC 2217 support warn and degrade safely
RFC 2217 bridge client mode: A bridge can dial a device server and synchronize its serial parameters from the link's other endpoint. Parameters are sent once negotiation succeeds and only changes are sent afterward; remote replies are recorded in the link messages but never applied back to the local serial port
Remote control-line status: RFC 2217 connections show the remote CTS, DSR, RI and DCD states, making hardware handshaking behind a device server directly observable
Fixes
RFC 2217 negotiation: The access server now answers a client's WILL with DO. It previously worked only with clients that also send DO, such as pyserial; a client that opens with WILL alone waited until it timed out and fell back to a plain socket
RFC 2217 negotiation no longer ping-pongs: Answers are tracked per option and sent only when they change something. Two Serial Port Utility bridges pointed at each other used to exchange WILL/DO forever
RFC 2217 compatibility: COM-PORT-OPTION refusals are now interpreted by role, fixing parameter delivery after negotiation with ser2net
Terminal passthrough on network connections: Fixed keyboard passthrough checking only the local serial handle, which made typing ineffective on TCP, UDP and RFC 2217 connections
Bridge peer events: A peer arriving on the device end no longer opens a negotiation with the network end
Download
| Platform | File |
| --- | --- |
| Windows 10 1809 or later, 64-bit | serial_port_utility_*.exe |
| macOS 12 or later, Apple Silicon | SerialPortUtility-*.dmg |
| Linux x86_64 (Ubuntu 22.04 or later) | serial-port-utility-*-linux-x86_64.tar.gz |
First-launch notes for each platform — Gatekeeper on macOS, the runtime libraries on Linux —
are in the README.
Connection activity lamps: The connection group gains interactive TX/RX and control-line indicator lamps that blink to reflect live traffic and control-line state; the classic control-line UI is retired in favour of the lamps
Serial control lines: Added serial control line handling with a new Control Lines tab in the settings dialog
Modbus request builder: Added a Modbus request builder to the Tools menu
Per-field quick settings: Quick settings are now available per field across all groups, with the picker moved into the settings dialog
Line Ending combo: Replaced the send auto-feed checkbox with a Line Ending combo
Restore last connection: Automatically restores the connection that was open at last exit
Terminal caret & honest Tx metrics: The terminal mode shows a caret and reports real Tx counts
UI Improvements
TCP/UDP mode UI: Silenced the server-error popup and polished the TCP/UDP mode UI
Toolbar: Reworked the log-recording and quick-settings toolbar controls
UI alignment & polish: Unified the receive Auto FL and send Loop rows, aligned the Line Ending and Append Checksum combos, and more
Fixes & Enhancements
Settings defaults: Seeded and guarded the remaining Log/Display defaults in the settings panel; never store empty Rx/Tx time formats
.spu session loading: Parse .spu bool flags with toBool so saved true values survive reload
Internationalization: Label the format radios Text, not ASCII, in Chinese
Log directory: Create the log directory before opening the log file