Timezone issue on ng-model bind

[tux1337]

I have a web formular which loads previously saved values to a datetimepicker field.

When I bind the saved value to the ng-model of the field, for example:
2018-06-07T21:15:00.000Z
it is shown as UTC in the formular and is not calculated to my timezone which it works when I pick it over the picker dialog.

If I save this value once more, it is calculated from my current timezone to a UTC value which changes the loaded value (in my case) to:
2018-06-07T19:15:00.000Z

Implementation of the field:
<input mdc-datetime-picker date="true" time="true" type="text" id="time" short-time="true" placeholder="soon as possible" click-outside-to-close="false" auto-ok="true" min-date="StartTimeMinDate" max-date="StartTimeMaxDate" format="YYYY-MM-DD HH:mm" ng-model="MigrationData.StartTime" edit-input="false" show-icon="true" ng-model-options="{lang: 'en'}" ></input>

The issue is reproducable with
version 1.15.2
version 1.15.1

The behaviour doesn't change if I add the "timezone: 'utc'" attribute to ng-model-options.
My expectation of this option is, that the value in the field is UTC. But also with this option the value is local time.

[tux1337]

I was able to solve it:
You have to use format="YYYY-MM-DD HH:mmZ"

This was not clear for me after studying the documentation. Maybe we can improve this in the readme.

[hexadecy]

@tux1337 can you please make a suggestion to improve the readme?

[hexadecy]

Readme improved