Admin Order Reports throw exception in en_GB locale

[JacobDrummond]

Environment

1. PHP 5.6.16
2. MySQL 5.6.21-log
3. Magento 2.1.3
4. Apache 2.4.17

Steps to reproduce

1. In System > All Users > User > [You], set the interface locale to English (United Kingdom):
   
2. In Reports > Sales > Orders, execute a query involving days above 12 e.g. 31/11//2016, but not 10/11/2016:
3. Click "Show Report"

Expected result

1. Magento generates Order Report between the dates specified

Actual result

1. (Exception): Invalid input date format '31/12/2015':

General date/locale issues

• Although JS datepickers follow the locale set in "System > Users", PHP doesn't which causes these validation errors.
• Cannot create Customer with Date of Birth in Magento 2.1 (en_GB locale) #6323, a similar issue, has already been resolved by @slavvka.

[veloraven]

@JacobDrummond thank you for your report.
This issue was fixed in developer branch but was not fixed in 2.1 yet.
We have internal ticket for this version: MAGETWO-57839

[JacobDrummond]

@veloraven, thanks for your feedback.

When will these develop fixes be included in a release?

In general, what is your develop-to-release workflow?

[webdevlabo]

@JacobDrummond It can happen because of locale: try M/D/Y format instead and check if it works.

[JacobDrummond]

@webdevlabo, yes that's the known fix :)

The whole point of this bug report is that Magento should be implementing locale consistently across JS and PHP.

[janeblonde]

@veloraven this has been reported a few times since October, do you have an ETA on when it might be fixed? or is there a way we can see the code that needs to be modified from the developers branch?

[rogerrogerrogerroger]

We are based in UK with latest Magento 2.1.3, is there an update on when the fix will be released?

[marcosdsdba]

@veloraven I performed the tests and the error persists in versions 2.1.5 and 2.1.6
I opened an issue #9432