LuminTech.AI — Linux ARM64 hardware-feedback pilot October 9, 2026 | v1.6.28 build49 | unsigned test package, installs fresh or upgrades in place Support and security: info@lumintech.ai START HERE This separate Linux package is for testing on your Spark, not replacing your working Windows or Mac app. Keep all existing desktop projects and app-data folders unchanged. Windows-to-server migration qualification is deferred; it is still required before we call the complete migration pilot accepted. NEW IN 1.6.28: UPGRADE IN PLACE If your Spark already runs an earlier Linux preview (1.6.23 to 1.6.26), you can now install this package over it. Your server keeps its projects, settings, memory, server identity and paired devices. See "UPGRADING AN EXISTING SERVER". PACKAGE IDENTITY File: lumintech-private-server-preview_1.6.28-49_arm64.deb Size: 321937440 bytes SHA-256: 5a0ffd81df99050b9c3bf6152641fb90173a1ab642b1380610e7e0ac3c339703 Installed payload inventory SHA-256: c2cc015be2d901a14d6828d01fb82d85d98c4934f0c2c55334c4736565058367 Match the exact filename, size and checksum above, not just the version. A checksum detects changed bytes; it does not authenticate the publisher. REQUIREMENTS Ubuntu 24.04 ARM64 with systemd, a graphical desktop, browser, administrator access, internet for account/network setup, and several GB free plus room for your projects/backups. An upgrade also needs free space for one copy of the server's data (projects included) while it runs. Setup detects the host and refuses unsupported systems. This is not an x86/AMD64 Linux, Windows, or macOS package. Do not alter detected OS values or disable security checks. 1. DOWNLOAD AND VERIFY ON THE SPARK On the Linux server, open https://downloads.lumintech.ai and choose the download button, or download it in a terminal: curl -fLO https://downloads.lumintech.ai/downloads/linux-pilot/5a0ffd81df99050b9c3bf6152641fb90173a1ab642b1380610e7e0ac3c339703/lumintech-private-server-preview_1.6.28-49_arm64.deb An interrupted download can be resumed with curl -C - and the same URL. In the download folder, verify: sha256sum lumintech-private-server-preview_1.6.28-49_arm64.deb Compare all 64 hexadecimal characters against the SHA-256 above. Stop if the size or checksum differs. Do NOT extract the .deb with Archive Manager. It is an installation package, not a ZIP to unpack. 2A. FRESH INSTALL (no LuminTech.AI server on this machine yet) Open a terminal in the download folder and run: sudo apt install ./lumintech-private-server-preview_1.6.28-49_arm64.deb Installation itself does not start the server, change projects, or enroll a private network. Continue with "GUIDED SERVER SETUP". 2B. UPGRADING AN EXISTING SERVER (an earlier Linux preview is set up) Close LuminTech.AI Server Setup, then run the same command: sudo apt install ./lumintech-private-server-preview_1.6.28-49_arm64.deb The upgrade checks that the running server is healthy, stops it (a few minutes of downtime), saves a snapshot of its data, installs the new program, updates the server's configuration, starts it again and checks that the server identity, projects and services are intact. Watch for the line "upgrade complete" in the output. Your devices reconnect to the same address; no new pairing or Setup run is needed. If the new version fails any check, the upgrade rolls back by itself: the server returns to the previous version with its data exactly as it was before the upgrade, and apt reports an error for this package. The output names a log folder under /var/lib/lumintech-package-upgrades/. Send that folder's "log" file to support. Until a fixed package is available, apt will show this package as not fully configured; your server keeps running the previous version meanwhile. Do not delete anything under /var/lib or /opt/lumintech. The upgrade keeps one snapshot of the data from before the most recent successful upgrade in /var/lib/lumintech-package-upgrades/ and the previous program in /opt/lumintech/previous. The next successful upgrade replaces them. Downgrading to an older package is not supported and is refused. If you set up an earlier preview and would rather start over with an empty server, ask support for the "remove the old version" procedure. It moves the old server's data into a dated backup folder; it never deletes it. 3. GUIDED SERVER SETUP (fresh installs) Open "LuminTech.AI Server Setup (Preview)" from the applications menu. Choose "Set up my Linux server". Review detected OS/architecture. Choose dedicated, non-overlapping project and backup locations offered by Setup. Follow the official Tailscale installation/sign-in handoff, then Check connection. Do not change unrelated routes, accounts or services to pass. Review the displayed fresh-install plan before approving OS consent. Follow the private HTTPS and owner-activation steps. Keep activation codes private and compare server identity as instructed. Do not enable public Tailscale Funnel or expose the server's ports to the public internet. 4. TEST THE SERVER WORKSPACE Open the private HTTPS address supplied by Setup and enroll the owner browser. Connect your own ChatGPT/Codex account through its official login flow. Create a disposable project. In Connections, run the workspace check. Try one small chat that creates and reads a synthetic text file, upload a non-sensitive document, and check RecordorAI recall. A live agent request uses your own subscription allowance. After an upgrade, also confirm your existing projects, files and memory are as you left them. 5. LAPTOP AND PHONE Install/sign in to Tailscale on each device and join the same private network. Open the exact private server address from Setup; approve device enrollment. On the existing owner device, open Connect device. The default "Workspace client" is restricted. For your OWN trusted laptop or phone, choose "My trusted owner device", read the full-control warning and explicitly confirm. Codes expire within ten minutes; sessions normally last seven days. Codes never belong in a link, QR code or support message. Use this address, NOT the public LuminTech.AI Cloud page, for this test. 6. BACKUP AND ENGINE RECOVERY On the Linux server, use Setup to create a verified backup of the workspace and test its isolated reconstruction. Live data must remain in place. If Setup reports that a backup needs service recovery, follow its "Review engine recovery" confirmation. Do not delete journals, locks or data if recovery is unavailable. WHAT PASSED / WHAT YOU ARE TESTING Release checks: full source test suite, types and lint; the exact package in isolated Ubuntu 24.04 ARM64 systemd containers. Fresh install and guided-setup start. In-place upgrades from each earlier published preview (1.6.23, 1.6.24, 1.6.25 and 1.6.26) kept the server identity, credentials, projects, data files and desktop Setup progress, rebound the installation record to this release, and passed the server's own backup checks. Deliberately broken builds (engine fails to start; configuration update fails) were rolled back automatically with the data restored and the previous version serving. Not yet accepted: physical Spark graphical privilege prompts, Tailscale/TLS, live account/model work, physical laptop/phone journey, Windows capture/ migration, signing and production/cross-host restore. The independent automatic updater is NOT included; upgrades happen only when you install a package. Home Assistant and local models/PAIR are not covered by these tests. FEEDBACK Send the first failing step, exact error, screenshot, OS/browser versions, package checksum and what still works to info@lumintech.ai. Never send login codes, access tokens, private keys, raw app data or backups. Preserve originals.