Style rendering in Outlook changed: Roboto font weight is displayed bold

Question

At my organization we use ServiceNow as ITSM solution, which sends emails to our users who use Outlook.
I worked on some of these notifications as ServiceNow developer, had some struggles with the styling, weird rendering, big differences between desktop app and OWA, etc. All that was sorted out to an acceptable level, we went live with notifications in May 2022.
However, sometime in October 2022, the notifications are displayed differently: where normal weight Roboto font is applied, it is displayed as bold in desktop app. OWA displays the font as it did before. At first I thought this is a ServiceNow issue, but then I realized that the styling issue is not only for newly received emails, but also for already received ones, including the testing emails back in May 2022.
I tried to ask for internal support, but the only answer I get is that this is a ServiceNow issue, which I don't understand how could be for emails sent more than half a year ago.
Does anyone have an idea what could have happened? If this is on Outlook side, can you recommend what to ask from our administrators to investigate?
I tried to ask what are the supported web fonts in our Outlook desktop version, but I didn't receive an answer and I am not even sure if the question makes sense.
Thank you in advance!

Answer 1

Sounds like your emails are in HTML. Therefore, in HTML, styling is controlled either by using the standard HTML elements like H1, strong, etc or using custom styling. Ideally your emails are using standard HTML elements and therefore the client is responsible for formatting them. You have no control over the formatting and changes can occur over time. That is why HTML is so useful. You provide the data and the client handles the rendering.

If you are using custom styling (or you don't want to rely on default behavior) then you have to include either a link to a CSS file (which the client may block) or put your styling inline. In this case you are completely responsible for the styling. If the styling is wrong you have to fix the HTML. But since this is an HTML mail message then once the message is sent you cannot change the formatting anymore.

So we are back to the question of whether you're relying on the default client formatting or you have put the formatting in the email directly. If you're using a custom font then that pretty much mandates you use custom formatting and that the client allows the downloading of external files (which is a security risk). If you're using the default formatting then you can go into the Outlook client options and change the formatting based upon the stationery used (and this is customizable by the end user).