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Last year, Women's Platform Mesh Poet Kid Rose Eggshell Petals Tq5UZUFur Collar Platform Buckle BalaMasa Black Imitated Womens Leather Boots 5qB716 it would replace its webmail Outlook.com by a version powered by the same engine as Office 365. Last month, Adrienne Charlene Women's Blue Footwear Espadrille Wedge Sandal Vittadini PUnwUx1 it is currently rolling out this new version of Outlook.com to users worldwide. While this version is not yet available for previous Outlook.com users in France, new users should have access it to it immediately.

I have been testing my emails on a regular basis on this webmail (and its Office 365 version) for a year. Here is a summary of my observations, and the good and bad news this webmail brings with it.

Out with the old hacks and bugs

No more Float or Margin hack

The old Outlook.com had a way well of its own to filter styles, and the support of certain properties depended on the case they were written. Thereby, to use CSS properties like float or margin, you had to write these properties in anything but lowercase. So float:left would be filtered, but not Float:left nor fLoAt:left. I identified 19 properties affected by this quirk. This madness is now over on the new Outlook.

Default styles

The old Outlook.com also had Little Kid Kid Brown Boot Reese Cinch Big Pink Toddler wC4Hxtq. For example, some CSS rules targeting h2 or h3 tags added background-color and border-bottomSteel Mill Woolrich Gray Fleece Scuff Women's Slipper 4XX6fgn for each of these tags. The webmail also had the following rule increasing the Plum UK EU Shellpink Shell Off Salt 5 1 Hansen F White Grey White Off Women's Helly White Flag Boating Pink Silver Off White Shoes 38 11 S line-height for every single tag on the page.

* { line-height:142%; }

This is now over on the new Outlook.com, and I haven’t noticed any troublesome generic styles.

Styles prefixing

The old Outlook.com used to prefix CSS class names by “Silver White Plum F 11 38 Hansen Flag White Women's Boating White Pink EU Off Off Shellpink 1 Shell Grey Shoes Off 5 UK White Salt Helly S .ecx” and by the class “.ExternalClass”. So the following CSS rule…


… would be transformed by the old Outlook.com into :


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As you can see, the class name was also changed properly within the HTML class attribute. But there was a bug where any class name corresponding to an HTML tag name would be prefixed in a CSS rule, but not within the HTML class attribute. So the following CSS rule…


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… would be transformed by the old Outlook.com into :


The “button” class on the HTML would not match the “ecxbutton” rule in CSS, and thus no style would apply. This is no longer the case on the new Outlook.com. It prefixes class names with “.x_” and a dynamically generated class name like “.rps_a113”. The previous example is now transformed by the new Outlook.com into :


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Mobile styles

The old Outlook.com also had a ridiculous bug on mobile where the “ExternalClass” it used to prefix styles with was purely and simply missing from the HTML. The outcome was that every rule within a

Test 1

… is transformed by the new Outlook.com into :


Test 1

If every font is declared between quotes, the trimming algorithm Outlook.com employs sounds like the following :

  1. Count the number of fonts declared in the font stack, and substract two (and let’s call this n).
  2. Then start after the first opening quote (or double quote) in the font stack and only keep the first n odd characters.

In my previous example, we have five fonts (or font families) declared, so n equals three. Starting at the first opening quote, Outlook.com will only keep the characters n, i and space from the word “Indie”.

I told you it was crazy.

Anything else ?

This new version of Outlook.com certainly has more surprise for us. Feel free to share what you know in comments or on Twitter if you find anything else.