Compatibility
This document records tested LLM platforms, engine versions, known limitations, and regressions for Invariant LLM Connect.
The goal is to compare Connect against the same workloads in conventional browsers and make compatibility and performance visible during development.
Engine and build measurements should use equivalent workloads and record the same resource metrics for each comparison.
Test Matrix Template
| Date | Connect version | Engine/base | Platform | Platform version | URL type | Result | Notes |
|---|---|---|---|---|---|---|---|
| 2026-09-16 | 0.2.0 retired prototype | WebView2 153.0.4234.32 | Local HTTP endpoint (Apache) | Not reported | localhost | Retired | Historical workflow result only. Chromium-based and not a product baseline. |
| 2026-09-17 | Gecko development | Gecko 158.0a1 artifact build | Runtime engine | N/A | local | Pass | Live Windows process tree loads xul.dll; no WebView2, Edge, Chromium, Chrome ELF, or CEF modules detected. UI workflow testing remains pending. |
| 2026-09-18 | 0.3.0 | Gecko 158.0a1 full source build | Windows install/update runtime | N/A | local | Pass | Branded EXE installed per-user, same installer completed an in-place update, profile remained intact, and the relaunched installed process loaded xul.dll with no Chromium-family modules. |
| 2026-09-19 | 0.3.0 | Gecko 158.0a1 full source build | Open WebUI | 0.11.3 update offered | localhost | Partial | Login and LM Studio-backed communication work. App status remained on Loading and app Settings/About controls were missing; fixes prepared for 0.3.1. |
| 2026-09-19 | 0.3.1 | Gecko 158.0a1 full source build | Windows update runtime | N/A | local | Pass | In-place update installed and relaunched with the preserved profile. Installed archive contains the status fix, visible Platform label, and Settings/About menu; live process verification loads xul.dll with no Chromium-family modules. Visual control confirmation remains pending. |
| 2026-09-19 | 0.3.1 | Gecko 158.0a1 full source build | Open WebUI shell layout | 0.11.3 update offered | localhost | Partial | Connected status, Platform control, and settings gear render correctly. User requested Invariant identity above the tabs and tabs on the navigation-control row; layout update prepared for 0.3.2. |
| 2026-09-19 | 0.3.2 | Gecko 158.0a1 full source build | Windows toolbar-layout update | N/A | local | Pass | In-place update installed with profile preserved. Native tab container is placed after reload in the navigation row; Invariant identity is placed in the title row. Gecko-only live runtime verification passed; visual confirmation remains pending. |
| 2026-09-19 | 0.5.0 | Gecko 158.0a1 full source build | Windows install/update runtime | N/A | local | Pass | Transactional per-user installer replaced 0.3.2, preserved the profile, registered 0.5.0, and relaunched successfully. The live process loads xul.dll with no Chromium-family modules; forbidden Mozilla updater and telemetry helper binaries are absent. |
| 2026-09-19 | 0.5.0 | Gecko 158.0a1 full source build | Open WebUI external-link boundary | 0.11.3 update offered | localhost/external HTTPS | Partial | Automated boundary tests passed, but unsupported eager module loading prevented the custom chrome from initializing, hiding the brand, moved tabs, Platform control, Settings, and About. |
| 2026-09-20 | 0.5.1 | Gecko 158.0a1 full source build | Branded shell startup | Open WebUI 0.11.3 | localhost | Pass | Updater modules use Gecko's supported resource:///modules path. Branding and controls initialize independently of updater availability, toolbar targets are awaited, and live isolated-profile startup wrote the 0.5.1 chrome initialization marker. Installed archive and Gecko-only runtime checks pass; user visual confirmation remains pending. |
| 2026-09-20 | 0.6.0 | Gecko 158.0a1 full source build | External-link policy | Open WebUI 0.11.3 | localhost/external HTTPS | Pass | Configured platform origins remain in Connect; ordinary external links use a marked External Preview; release, update, authentication, download, unsupported-protocol, and pop-up destinations use the system browser. Preview/System/Ask settings and the exact Open WebUI GitHub release route have automated coverage. Installed archive, live startup, and Gecko-only checks pass; hands-on link confirmation remains pending. |
| TBD | Gecko development | Gecko 158.0a1 | Open WebUI | TBD | local/LAN/remote | Not tested | Initial hands-on target |
| TBD | TBD | Gecko TBD | AnythingLLM | TBD | local/LAN/remote | Not tested | Initial target |
| TBD | TBD | Gecko TBD | LibreChat | TBD | local/LAN/remote | Not tested | Initial target |
Result Values
Use consistent status terms:
- Pass: core platform workflows work without Connect-specific issues
- Partial: platform loads, but one or more important workflows fail
- Fail: platform cannot be used
- Regression: behavior worked in an earlier Connect build and no longer works
- Not tested: no current result
Workflows To Exercise
For each hosted platform, test:
- initial load
- login or local access flow
- new chat
- multi-turn chat
- model selector or platform-native model controls
- streaming responses
- file upload where supported
- image or media display where supported
- settings navigation
- internal links/routes
- ordinary external-link preview and sensitive-destination handoff to system browser
- multiple tabs with the same platform
- tabs with different platforms
- manual suspension and restore
- idle behavior after generation completes
Performance Measurements
For each tested workload, record the equivalent stock-browser comparison where possible:
| Date | Workload | Browser | Browser-controlled RAM | Idle CPU | Idle network | GPU notes |
|---|---|---|---|---|---|---|
| 2026-09-16 | One local endpoint tab idle | Invariant LLM Connect 0.1.1 / WebView2 | 395.1 MB working set across 7 app/WebView processes | 0% over 5 seconds | Not measured | Not measured; preliminary sample, no stock-browser comparison yet |
| 2026-09-19 | Open WebUI login and LM Studio communication | Invariant LLM Connect 0.3.0 / Gecko 158.0a1 | Approximately 250-360 MB observed | Not measured | Not measured | User-observed working range; exact tab/process count and comparison baseline not yet recorded |
| TBD | Open WebUI identical workload | Firefox | TBD | TBD | TBD | TBD |
| TBD | Open WebUI identical workload | Chromium | TBD | TBD | TBD | TBD |
| TBD | Open WebUI identical workload | Invariant LLM Connect | TBD | TBD | TBD | TBD |
The meaningful comparison is Connect versus a conventional browser running the same LLM interface, not Connect versus no browser.
Known Limitations
- The active Windows development build uses Gecko. The old WebView2 prototype is retired and excluded from testing.
- Artifact mode retains Firefox Nightly version metadata in the precompiled launcher; the full source and installed builds carry Invariant identity.
- The Windows development installer is unsigned; production signing and a release update feed remain pending.
- Windows and Linux are active release targets. The current Linux baseline is x86_64 glibc; musl and ARM64 are not currently supported.
- External authentication flows have not been fully tested.
- One preliminary local-endpoint resource sample has been collected. Equivalent Firefox/Chromium and real Open WebUI workload comparisons remain outstanding.
Regressions
- Fixed in 0.6.0: Open WebUI's external update link opened GitHub in a Connect tab. Release and update destinations now bypass Connect and use the operating system browser, while ordinary external links use the marked preview policy.
- Fixed in 0.5.1: The 0.5.0 updater import could stop all custom chrome initialization. Branding, tab placement, Platform, Settings, and About now initialize independently, while updater failures remain visible inside Settings.
Compatibility Principles
- Do not tune only for a single named platform.
- User-defined endpoints must remain supported.
- External authentication should be supported only through controlled temporary flows needed by configured platforms.
- Critical web security behavior must not be disabled to make a platform appear compatible.
- Compatibility claims should be backed by recorded platform, version, engine, and date.