Hi All,

For the past couple of months I've been promoting the idea of having Long Term 
Support (LTS) feature releases for ClamAV within internal Talos communications.

For the purposes of this discussion:

  *   A "feature release" is a version starting with MAJOR.MINOR.0 to include 
all PATCH versions. I.e. ClamAV 0.103.0, 0.103.1, 0.103.2, and 0.103.3 are all 
within the same "feature release".
  *   A "patch version" is a specific MAJOR.MINOR.PATCH version. E.g. 0.103.4 
would be the next "patch version" in the 0.103 "feature release".

My interest in starting an LTS program came about because we have been getting 
(understandable) pressure from management to have shorter development times for 
feature versions with more targeted feature sets.  What this means is that you 
would see more frequent feature releases, possibly as many as ~5 per year.  
Some of the features in a given feature release would be things the community 
cares about, while others may be by request of a different team within Talos or 

But I couldn't in good conscience start pumping out new feature releases every 
2-4 months and expect everyone to keep up. And at that rate it would not be 
possible for us to make critical patch versions for every feature release 
within the two years, or even one year.  So in order to get features out faster 
it became clear to me that we will need to define specific feature release for 
which we promise to backport security fixes for some amount of time.

This raised a few obvious questions:

  *   Which feature release do we start with?
  *   Do we have to continue serving signature database content to every patch 
version in an LTS release?
  *   How often should we select a new feature release for LTS?
  *   How long is "long term support" anyways?

We've been talking about this off and on for the past couple of month.  This is 
what I came up with....

Which feature version do we start with?

We had initially settled on 0.104 as the first LTS version, for basically two 

-          Joel really wants to make sure people have the latest freshclam 
features, particularly those found in 0.103.2 and 0.103.3, to reduce bandwidth 

-          I don't want to keep fixing glitchy autotools package detection 
issues for years to come.

But after seeing the (very much unexpected) reaction to the switch CMake... 
it's clear to me now that we need to start the LTS program with 0.103.

Do we have to continue serving database content to every patch version in an 
LTS release?


LTS means that we will promise to continue providing patch versions for a given 
feature release.
I.e. you will get critical fixes in 0.103.4, 0.103.5, 0.103.6, etc. as needed 
until End of Life (EOL) for the 0.103 feature release.

I need to stress that it doesn't mean people should or will be allowed to 
continue using vulnerable or otherwise problematic versions such as 0.103.0 and 
0.103.1 just because they belong to an LTS feature release. We will reserve the 
right to at some point begin to block older patch versions like 0.103.0 from 
downloading databases to force people to use newer patch versions.

How often should we select a new feature release for LTS?

Some products, like Ubuntu, do a new LTS ever 2 years with support for 5 years. 
 2 years feels like a long time but, as much as I want to get people using the 
latest features, our team is pretty small.  The more frequently we a release 
for long term support, the more work each security release will be.  We would 
be required to create and test a new patch version for the current stable 
feature release plus a collection of LTS releases. If we did an LTS every year, 
that would be too much.

I think 2 years is probably a good number.

How long is "long term support" anyways?

As noted above and elsewhere, Ubuntu and RHEL/CentOS support LTS versions for 5 
years.  That's a long time, and more than our team could agree to.
After a bunch of discussion, we think 3 years is a good number.

To summarize, I'm proposing a Long Term Support (LTS) program for ClamAV 
starting with the 0.103 feature release.  This means:

  1.  We will promise to provide critical patch versions (0.103.4, .5., .6, 
etc.) as needed until the LTS end-of-life.
This does not mean that the original 0.103.0 or other problematic patch 
versions within the series will continue to "work".
Users MUST be willing to upgrade to newer patch versions within a given LTS 

  2.  Each LTS release would be supported for three (3) years from the first 
(.0) version.

0.103.0 was published in August 2020.  This means we would continue to provide 
critical patch versions for 0.103 until August 2023.

  3.  We will aim to select a new LTS feature release every two (2) years.

With 0.103 starting the LTS program, that means that whichever feature release 
is to be published near abouts August 2022 is the likely candidate for the next 
LTS release.

  1.  When a security fix is required, we'll publish a patch version for the 
latest feature release as well as all affected active LTS feature releases.

  2.  We will document the LTS policy and add an end-of-life version table to 

I would like your feedback.


Micah Snyder
Cisco Systems, Inc.


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