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Are Modern Public Folders the best destination for your data?

Jun 2, 2017 by Kitty Lai

Following on from our previous post ‘ Do you know what’s in your Public Folders?’, this blog series will explore each possible option for migrating legacy public folder data, and try to shed a light on the most appropriate target for your different data types.

A ‘Modern’ world

We’re starting with modern public folders. Why? Partly because many people assume that they are the most logical option for this data (the name certainly suggests this), and in IT, ‘modern’ is usually the direction we’re aiming for. At face value modern public folders might seem like the best fit, but it all comes down to your own requirements and how you plan to use your data. Before we begin to evaluate modern public folders as a destination, we’ll take a quick step backwards to explain the functionality, and how it came about.

Modern public folders were introduced with Exchange 2013 (they are only available in Exchange 2013, 2016 and Exchange Online). The feature brought minimal changes to the end user’s experience, but much of the processes and systems which powered the legacy feature were updated in the modernized version. As you can see below, public folder databases were replaced by mailboxes, and each public folder mailbox includes the complete public folder hierarchy. There is only a single writable copy of the hierarchy.

Legacy vs. Modern – What’s the difference?

Exchange Online Public Folders

If you’re using modern public folders in Exchange Online, there are a variety of additional benefits, including:

  • Storage at no extra cost. You can create up to 1000 public folders with a quota of 50GB each (50TB in total).
  • Once you’ve migrated to the service, and created the first public folder mailbox, Microsoft manages the storage for your public folder mailboxes.
  • Cross-premises access is possible. Exchange Online users can still access on-premises public folders, and vice versa: Exchange 2013/16 on-premises users can access public folders in Exchange Online.
  • The tenant admin can also do folder management in the Exchange Admin Center.

So, modern public folders have lots of space, as well as flexible management and access options, but what should you put in there?

Example Use Cases for Modern Public Folders:

  • A lot of organizations use shared calendars to share events or create rosters, or schedules. These can be created using modern public folders (here’s a useful blog demonstrating how to create them).
  • Modern public folders can be used to store an team/organization’s shared contacts.
  • You can move emails from various mailboxes to public folders for a specific purpose, like coordinating project work and collecting offers or purchase orders. Conversations can be collected so everyone on the team can access them, and this function is particularly good for large teams and long-term projects, as there is no limit of usage or scalability issues.
  • The feature can be used to create an electronic bulletin board for general, organization-wide announcements.
  • They can be used as an email enabled folder for inbound messages with users maintaining their own ‘read’ status. Teams are also able to send an email from the folder when collaborating with others.
  • They can be used to create a task list for certain teams, or groups.


Modern public folders are designed to provide an easy and effective way to collect, organize, and share information among users in large organizations. They can be mail-enabled to receive messages, act as shared calendars, and help with task management structures. Additionally, modern public folders can be created and managed by users, and are therefore easy and quick to set up and use.


Modern public folders were never intended to archive data or share documents, meaning that they don’t provide important document management features (such as automatic notifications of content changes). Modern public folders have better compliance and search functionality than their predecessors, with legal hold and eDiscovery available, but you can only search the entire hierarchy, not specific folders, so it still lacks some granularity. There is also no option to set retention policies on the data.

What should you consider?

When looking at what option best suits your legacy public folder data there are several aspects you must consider:

Feature parity – Do you need a shared calendar or another specific function? The product you choose may requires compatibility with another product, such as integration with Outlook, or mobile access.

Scalability – Public folders were intended for whole organizations, and products such as Office 365 Groups and Shared mailboxes don’t scale particularly well with hundreds or thousands of users, so taking into consideration the size of your user based is important.

User Experience and Client access – You might not want to be limited to just Outlook or Outlook Web App, or prefer the availability of mobile experience.

Search experience and discoverability – Public folders have quite limited search capabilities, so a product with extended capabilities may be beneficial to your needs.

 Customizability and extensibility – A customizable platform with extensibility is especially useful, particularly for situations like storing forms and automating different tasks.

 Management and permissions – Public folders also traditionally operate with a ‘self-service’ model, where users can create a folder and populate it when they need to. Alternatives like Office 365 do offer this model but others might require that the feature is managed by the administrator.

Compliance and data governance – For Enterprise customers this is hugely important, as this includes data residency (for example, German customers might insist their data is stored in German data centres) and not every product can implement this. Combining this with eDiscovery, legal holds and legal holds, these are very important aspects to consider.

‘Social features’ and analytics – If you require social features such as ‘likes’ or ‘comments’ (which are available in chat-based options like Microsoft Teams), or analytics on usage.

It’s clear that modern public folders are a substantial improvement from their legacy counterpart, but that doesn’t necessarily mean they’re your only option. It’s all down to your data, and it’s crucial to understand what you have, before you try and move it. The following posts will go on to explore more alternatives for your legacy public folder data, so make sure you check back for the next blog in this series.