The support forum

Software updates & update channels

Feb 05, 2019


This topic describes how new program versions are announced via the built-in mechanism for software update checks.

It also describes how to move your installation to one of predefined update "channels" in order to make it see new versions faster or to delay their visibility.

Update checks

The program checks for updates by fetching a text page from:


* The URL is intentionally mangled to be uncrawlable by bots, but you are welcome to visit it manually.

The program also includes several bits of information with the request, including its own version, the OS version, license type and the reason for the request (manual, scheduled, etc.)

The update server uses this information to decide which version to offer, how critical it is and which part of the change log to include with it. See for a bit more on this.

Gradual roll-out

When a new version is shipped, it is made visible through update checks gradually, starting with 10% on the first day and then ramping up to the full 100% in about a week.

Whether or not a new version is made visible depends on the client's IP address. The IP is hashed first, the hash collapsed into 0-99 range and if the result happens to be below the current "visibility threshold", then a new version is announced. Otherwise the previous one is returned.

Feb 05, 2019


As of Release 77 (shipped in March 2017) the program checks for the presence of any Symantec-made software on the machine and indicates this in its update check request.

The reason behind this is explained in R77 release notes -

When the Symantec flag is present in a request, the update server will reply with a Bvckup's version number that is known not to trip Symantec's disaster of a heuristic detection. In practical terms this means that installations with any Symantec presence will usually see new Bvckup releases several weeks after they are shipped out.

It is possible to disable this delayed delivery. See below for details.

Feb 05, 2019

Update channels

Symantec-specific behavior is an example of an "update channel".

Each channel has its own "latest version", which is updated according to the channel's rules. A channel is identified by its name, which is set in the engine's settings as described below.

There are currently 3 public channels:

⦁    newest      -  the latest and the greatest public release
⦁    stable        -  the latest "recommended" public release
⦁    symantec  -  as per above, for those with Symantec presence

When a release is going through the gradual roll-out "stable" points at a preceding version, and "newest" - surprise, at the latest one. Once a release roll-out is over, both point at the same (latest) version.

Symantec channel is always lagging behind, usually by 2-3 weeks.

You can manually check current channel's version by appending "channel=xyz" to the query, e.g.


Feb 05, 2019

Default setup

By default, no update channel is configured in the program. That is, the update channel ID is left blank.

Manual update checks will always see the "newest" version.

Automatic (scheduled) checks will see either "newest" or "stable" version as dictated by the state of gradual roll-out, or "symantec" version if bvckup2 indicated a Symantec presence on the machine.

Feb 05, 2019

How to set an update channel

⦁    Use Notepad or any other text editor to create a plain text file
      called bvckup2-engine-override.ini in the following folder -

          %LocalAppData%\Bvckup2\engine\     if running in desktop mode
          %ProgramData%\\Bvckup2\engine\    if running in service mode

⦁    Add the following line to the file, save changes and exit the editor -


     whereby "xyz" is a name of the channel. Omit it altogether is you
     want to unset the channel.

⦁    Restart the program (or the service)

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