8.0 is not 10 years away

Hi All!

Occasionally, in various discussions, waiting for the next major release
is described as "maybe another 10 years", but I think that's a very
pessimistic prediction. It's more reasonable to expect it in half that
time, around 2020, and that is what we should base our decisions on.

The 10 year figure for gap between major releases comes from a single
data point - the fact that 5.0 came out in 2004, and 7.0 will succeed it
in 2015.

This leads to a worst case scenario, with annual releases, of 7.10 in
2025, and 8.0 in 2026. If you count releases, not years, the current
process already shrinks that to end with 7.6 in 2021, 8.0 in 2022.

But the very fact that 5.x is being superseded by 7.x should remind you
that that is not really a "normal" data point. While it's not impossible
that something similar will happen again, I think enough lessons have
been learned that 8.0 won't have to be abandoned the way 6.0 was.

I think it's not unreasonable to argue that 5.3 was a major release in
all but name; it came out when 6.0 should have, and contained many
features originally targetted for it. So according to the table on
Wikipedia, you have roughly the following timeline of release series:

• 1995: 1.0 (1 release, 2 years)
• 1997: 2.0 (1 release, 1 year)
• 1998: 3.0 (1 release, 2 years)
• 2000: 4.0, 4.1, 4.2, 4.3, 4.4 (5 releases, 4 years)
• 2004: 5.0, 5.1, 5.2 (3 releases, 5 years)
• 2009: 5.3, 5.4, 5.5, 5.6 (4 releases, 6 years)
• 2015: 7.0 ...

If we ignore the "pre-historic" releases of 1.0, 2.0, and 3.0, we have 3
data points, averaging out at 4 releases in 5 years. So it seems fairly
reasonable to predict, and indeed aim for:

• 2015: 7.0, 7.1, 7.2, 7.3, 7.4 (5 releases, 5 years, due to the annual
  release policy)
• 2020: 8.0 ...

So when deciding between rushing to add/remove something for 7.0 vs
waiting all the way until 8.0, remember to think in fives, not tens.

Regards,

--
Rowan Collins
[IMSoP]

Ralf Lang wrote on 20/01/2015 23:23:

Hi All!

Occasionally, in various discussions, waiting for the next major release
is described as "maybe another 10 years", but I think that's a very
pessimistic prediction. It's more reasonable to expect it in half that
time, around 2020, and that is what we should base our decisions on.

The 10 year figure for gap between major releases comes from a single
data point - the fact that 5.0 came out in 2004, and 7.0 will succeed it
in 2015.

This leads to a worst case scenario, with annual releases, of 7.10 in
2025, and 8.0 in 2026. If you count releases, not years, the current
process already shrinks that to end with 7.6 in 2021, 8.0 in 2022.
You are very right, but calculating with an experienced worst case +
20% is not a bad habit. PHP5 -> PHP7 isn't normal by itself.

Only where the worst case is due to external factors that might happen
again. In this case, it was due to things we are absolutely able to
avoid with the experience since then.

One can
hardly compare PHP5.0 and PHP5.4 and say it's the same release.

Agree; that's the core of my argument, that we are realistically
following a 5 year cycle between majors.

So when deciding between rushing to add/remove something for 7.0 vs
waiting all the way until 8.0, remember to think in fives, not tens.
That may be true, but remember "enterprise" distributions usually didn't
do version upgrades in the past if not strictly forced by mainstream use
cases. SLES 11 SP 2/3 broke this and added a PHP 5.3 and SLES 12 / RHEL
7 bring new policies, but they have already been released. The next
chance for serious BC breaks to hit "enterprise" distributions might be
8-9 years at worst, even calculating with 5 years till the next major
release.

Yes, that is worth bearing in mind. Of course, taken too literally, it
also implies that any changes we make now won't "hit" for 3-4 years, so
that we're always coding for some theoretical future use...

Still, for new features, knowing when you'll be able to rely on
deploying them everywhere is important, so point taken.

--
Rowan Collins
[IMSoP]