Drop support for Chrome versions < 51

[kzar]

Background

HTMLCollection, NodeList and CSSRuleList don't have iterator support in versions of Chrome before 51. So far ​we've worked around that.

Since version 51 of Chrome is already over a year old ​according to Wikipedia we've decided to drop support for earlier versions instead of adding further workarounds - see #5773.

What to change

• Increase the minimum supported Chrome version to 51, Opera to 38.
• Remove the iterator workarounds in adblockpluschrome/ext/common.js.
• Check for and remove any other workarounds which are no longer required.

[sebastian]

Chrome 49 is the last version that is compatible with Windows XP, and so far it didn't seem to have been too much pain to keep supporting it.

We never decided to drop support for a browser based on age, but on usage. So can we please first look at the usage numbers before making a decision to drop support for Chrome 49-50?

[kzar]

Fair enough, good point.

[sporz]

Acknowledged. Is there a deadline on this?

[Ross]

That's a good point. According to sites like W3Counter (​https://www.w3counter.com/globalstats.php) and netmarketshare (​https://www.netmarketshare.com/browser-market-share.aspx?qprid=2&qpcustomd=0) Chrome 49 is still the 6th or 7th most used browser.

[sebastian]

The distribution may vary between general web audience and Adblock Plus users, but Chrome 49 being quite dominant for a that old version would be expected, given that is what everybody on Windows XP (and Vista?) is stuck with.

Also in the past when we dropped support for old browser versions, the strongest motivation were improvements to our code that were blocked by incompatibility with old browser versions. However, except for dropping a ​trivial polyfill, there doesn't seem anything to gain by dropping support for Chrome 49-50 (and Opera 36-37).

[dbendel]

In order to help you finding an answer I looked into the data. These are the results:

• In general the migration to new browser version of the majority of users is pretty fast (less than a month to reach shares of over 80 percent).
• On 2017-11-13 26 percent of our users used chrome 62, 67 percent used chrome 61, the rest is distributed to older versions.
• Now over 2 percent of our users have a chrome version older or equal version 51. Since our total users number is not small, 2 percent is still a pretty high number.

In my opinion, a support of theses older versions could be still good idea, or one could send these users a notification that they are still using an old version and kindly asking them to up-date there version.

[sebastian]

I agree that 2% is still quite a lot. On the other hand, by discontinuing support for their browser version, we wouldn't lose these users immediately. They merely wouldn't receive updates anymore, and wouldn't be able to (re-)install Adblock Plus from the Chrome Web Store. But then again, as outlined above, for the time being, supporting Chrome 49+ isn't too much a hassle, that I would just stick to it, for now.

However, the relevant number here isn't for application == "chrome" && applicationVersion <= 51 but for platform == "chromium" && 49 <= platformVersion <= 50. As per the change suggested in this issue, we would keep supporting Chrome 51, but only drop support for versions older than that. Furthermore, users on Chrome < 49 are irrelevant as their browser version is already not supported anymore, but we might still see some requests in our data sent by older versions of Adblock Plus. Finally, just in case, make sure to consider the platform, not the application. When we talk about discontinuing a range of Chrome versions, we essentially talk about discontinuing any browser based on the respective Chromium version.

[dbendel]

Replying to dbendel:
Thank you very much for pointing that out! I will recalculate the numbers!

[dbendel]

Using this specification:

platform == "chromium" && 49 <= platformVersion <= 50

I get the following results:
On 2017-11-15 nearly 2 percent of the users uses a platform version between 49 (inclusive) and 50 (inclusive). However, this share naturally is constantly falling: since 2017-05-01 by about 1.6 percentage points.

[sebastian]

Thanks! Closing this issue, for now, for the reasons pointed out above.