The buttons still led to a dead GitHub page. 5.5.3 updated one of the two places these links live — the platforms menu on the connection screen keeps its own DOWNLOADS table, and it was missed, so it stayed on 0.1.0. Why it looked like a working link that did nothing: the stale entries used /releases/latest/download/<file>, and GitHub resolves `latest` by redirecting to the newest tag. Once 0.3.0 shipped, a link written for 0.1.0 resolved to /releases/download/v0.3.0/SecureBit.Chat_0.1.0_x64-setup.exe — a file that never existed under that tag. The browser navigated to GitHub and downloaded nothing. Both places now build their URLs from a DESKTOP_VERSION constant with the tag pinned, so the version is written once per file and a link cannot silently become invalid when a new release goes out. Adds tests/desktop-download-links.test.mjs, which fails the build if this drifts again: every source must derive URLs from that constant, /latest/ and hardcoded versions in filenames are rejected, and each generated URL is fetched to prove the asset exists. SKIP_NETWORK=1 skips the fetches offline.