In a somewhat cryptic message accompanying the link, OWS said, "Advanced users with special needs can download the Signal APK directly. Most users should not do this under normal circumstances."
There appears to have been some demand for the direct download, judging by the tweet posted below.
In a separate announcement, OWS said that encrypted video calling using Signal was now out of beta.
Any other calls made or received would be transmitted through the Signal service. However, one could make all calls through the Signal service by setting this in the options menu, he added.
Another privacy feature he cited was the displaying of Signal calls on iOS as being from "Signal user".
When Signal was integrated with the iOS CallKit feature, it was possible to answer calls from the lock screen with a single touch, initiate Signal calls through the native contacts app, and display Signal calls in the system's "recent calls" list.
Marlinspike said: "Integrating Signal that tightly with iOS can dramatically improve the experience, but it does have some potential downsides. Having Signal calls mixed with normal calls in the 'recent calls' list could be of concern for some users, since the 'recent calls' list is synced to iCloud by iOS if iCloud is enabled."
He said to balance these concerns, CallKit was enabled by default, but Signal calls would be displayed as being to/from "Signal user."
"This means that, by default, it's possible to answer Signal calls with one touch directly from the lock screen, but only 'Signal user' will appear in the 'recent calls' list (which is what could be synced to iCloud)."
Additionally, it was easy to opt in to displaying the name/number of an incoming Signal call if having that information in the "recent calls" list was not an issue.
"It is also possible to disable CallKit entirely if even having 'Signal user' in the call log is not desirable," Marlinspike said.