Licence and updates — Nixt Mail docs

Nixt Mail works as a mail client with or without a licence. A licence decides which edition this installation is and which paid capabilities it may use. This page explains how to see your licence, what it changes, what happens when it ends, and how updates are checked.

See your licence

Open Settings with ⌘, (Ctrl+, on Windows and Linux).
Choose AI and services.
Look at the Licence card at the top.

The card shows the edition’s name, a badge with the licence’s state, a sentence explaining it, and, for a licence covering more than one person, the number of seats, such as 10 seats.

Badge	What it means
No licence	There is no licence on this device. This is how a fresh installation starts.
Licensed	A licence issued by Nixt Mail, in date.
Expired — still working	A paid licence past its end date, inside its 14-day grace period.
Expired	A licence past its end date and any grace period.
Not valid	The licence file could not be read, was not issued by Nixt Mail, or was changed after it was issued.

The sentence under the badge is one of these:

Sentence	When
Nixt Mail is running unlicensed. Everything that works on this device works, and nothing is limited.	No licence.
Edition, licensed to holder.	A paid licence in date.
Edition evaluation — N days left.	An evaluation in date.
This licence expired. Paid capabilities keep working for N more days. Your mail is unaffected.	A paid licence in its grace period.
This licence expired. Paid capabilities are off; your mail and everything that runs on this device are unaffected.	A paid licence past its grace period.
Your evaluation has ended. Nixt Mail keeps sending and receiving mail; the capabilities you were trying are off.	An evaluation that has ended.
That licence file could not be read.	The file is damaged or not a licence.
That licence was not issued by Nixt Mail, or has been altered.	The signature does not match, or this copy of Nixt Mail cannot check licences.

What a licence changes

The edition

While a licence is in force, it decides which edition this installation is. Without one — or when a licence has ended or is not valid — Nixt Mail uses the edition this copy was built as. The edition decides which capabilities are offered at all; see Where AI and services run.

A licence can only confirm what is already in your copy. It cannot add a capability that was not built in.

Capabilities that need a licence

Capabilities that run on this device need no licence: Mail, Search, Calendar, Documents and Directory.

AI, which uses a model, needs a licence in force that includes it.

When a capability needs a licence it does not have, its row in Where AI and services run says why, instead of offering choices:

Sentence	What it means
Capability needs a licence. Everything on this device keeps working without one.	There is no licence.
Capability is not included in this licence.	The licence is valid but does not include it.
Capability stopped when the licence expired.	The licence has ended.
Capability needs a valid licence.	The licence is not valid.

When a licence ends

Your mail never stops. Sending, receiving, reading, filing and everything else that runs on this device keep working, whatever happens to a licence.
A paid licence keeps working for 14 days after its end date. During that time the badge reads Expired — still working and the sentence counts down the days.
An evaluation has no grace period. It ends on its end date.
After that, paid capabilities stop. Their rows in Where AI and services run say stopped when the licence expired, and offer no choices.
A licence with no end date does not expire.

Settings you chose, such as where AI runs and your API key, are kept, so they work again if you renew.

How your licence is checked

On this device. Nixt Mail checks the licence’s signature against a key built into the app. It does not contact Nixt Mail to do so, so a licence keeps working with no internet connection, and in networks that never reach the internet.
Every part is signed. The edition, the holder, the dates, the seats and the capabilities are all covered by the signature. A licence changed in any way after it was issued is Not valid, and nothing it claims is used.
It is not a secret. The licence is a signed file stored with Nixt Mail’s own application data, not in the keychain. A copy is of no use to anyone else.
Unreadable is the same as none. If the licence file cannot be read, Nixt Mail runs as unlicensed rather than stopping.

Check for updates

Open the updates section in either of these ways:

On macOS, choose Nixt Mail › Check for Updates….
On any system, open Settings › Updates.

The first time you open the section while Nixt Mail is running, it checks straight away. After that it shows the last result until you click Check now.

Part	What it shows
Nixt Mail version	The version running now, with The build running now. under it.
Check now	Checks again. Reads Checking… while it works.
Result	One line under it saying what the check found. A problem is in red.

While it checks, the result reads Checking for a newer build… — Asking the download service what it has.

The possible results:

Result	What it means	What to do
version is ready to install	A newer version, published by Nixt Mail, for your system and your licence. The line under it shows the edition, the download size, and the start of the file’s SHA-256 checksum.	Click Download. The download opens in your web browser. Or click Skip this version — see Skip a version.
Up to date	You already have this version or a newer one.	Nothing.
Not included in your licence	A correctly signed version exists, but for an edition your licence does not cover. The detail names that edition.	Nothing, unless you change your licence.
Not published by Nixt Mail	That build was not published by Nixt Mail, or has been altered. Nixt Mail refuses to offer it.	Do not install anything from that source. Check again later.
Older than the installed version	That build is older than the one installed. Older versions are never offered, even when correctly signed.	Nothing.
For a different platform	The version offered is for another operating system.	Check again later.
Could not be read	The check did not produce an answer. The detail says why.	See below.
Could not check for updates	The check failed. The reason follows.	Check your connection and click Check now.

Details you may see under Could not be read:

Detail	What it means
This build cannot check for updates.	This copy of Nixt Mail was built without an update service. Get new versions from the Download page.
Couldn’t reach Nixt Mail’s service. Everything already installed keeps working — this only affects fetching something new.	No connection to the update service.
The download service returned nothing. or That release manifest could not be read.	The answer was empty or damaged. Try again later.

Checking automatically

Above the result, Check for updates sets when Nixt Mail asks without being told to:

Only when I ask — only when this section is opened or Check now is clicked.
Each time Nixt Mail starts — once, as it starts.
Every day — as it starts, and again every day it stays open.

In a copy built without an update service, these choices are shown greyed out and the line under them says This build cannot check for updates, so there is nothing to schedule.

When an automatic check finds a version ready to install, a notice says Nixt Mail version is ready to install., with See it to open this section. Each version is announced once while Nixt Mail is open.

Skip a version

To stop being told about one version:

Open Settings › Updates.
Under the version that is ready to install, click Skip this version.

Nixt Mail no longer announces that version as it starts or during daily checks. The next newer version is announced as usual. The skipped version is still shown in this section with Download, and the line under it says it is skipped.

Skipped version, above the result, names the version you skipped. To be told about it again, click Stop skipping there, or beside the version.

Under the result, the section explains how updates are trusted: Nixt Mail checks the signature on a release before offering it, against a key carried in this build rather than one the service supplies, and what you are offered depends on your licence.

What the check protects against

Signed releases only. Information about a new version is signed, with a different key from the one that signs licences, and checked before anything in it is read.
No downgrades. An older version is refused even when correctly signed, so a version with a fixed problem cannot be put back.
Your edition only. A version for an edition your licence does not cover is not offered.
A checksum to compare. The start of the download’s SHA-256 checksum is shown with the offer.

Checking for updates sends your licence to the update service so it can answer for your edition. It sends nothing about your mail.

Nixt Mail › About Nixt Mail on macOS, or Help › About Nixt Mail on Windows and Linux, also shows the version number.