These are the results of the Exchange Server Questionnaire from August 2021.
First of all, I want to thank all of you who participated in the questionnaire. The results are pretty interesting. Even though, that the results are not 100% representative they provide a high-level view of the Exchange Organizations, the mail flow configurations, and the future plans regarding hybrid and Exchange Online.
With 55 replies the questionnaire is far from being a comprehensive representation of the Exchange organizations. But the answers provide an idea of the Exchange landscape used by organizations globally.
1. Exchange Server Versions in use (Production)
Exchange Server 2016 is the dominant version currently in use, followed by Exchange Server 2019. The vast majority of 93% runs modern Exchange Server versions. But there are still older and unsupported Exchange Server versions in use. 7% use Exchange Server 2010 and older.

2. How many Exchange Server systems do you operate?
76% of the organizations maintain up to ten Exchange servers. 20% prefer to rely on just one Exchange server. It is interesting that only 2 (not percent) plan to go hybrid or to move to Exchange Online.

3. How many mailboxes do your Exchange Servers host?
The majority of on-premises Exchange organizations are in the 1,000 – 10,000 mailboxes range. Nevertheless, the SMBs with 1 to 1,000 mailboxes adds up to 50% of the Exchange organizations that took part in this questionnaire. There are just a few organizations that host more than 50,000 mailboxes.

4. Do you use an on-premises or cloud-based SMTP gateway solution?
There are Exchange organizations that do not use an SMTP-Gateway solution as part of the mail-flow implementation. Thor organizations that do not use a gateway solution run 1 to 10 Exchange servers on-premises. The majority of those have less than 1,000 mailboxes but there are a few that are responsible for more than 1,000 mailboxes. That leaves the question of why an organization prefers to not secure mal-flow with a gateway.

5. Which product do you use as a gateway solution?
The use of SMTP gateways is a must, as you do not want to expose your domain member servers to the Internet, not even for the SMTP protocol. A majority of 28 answers for other gateways shows, that there are so many products available and that I did not choose valid answer options upfront.

The Other answers include:
- Cisco ESA
- Clearswift
- Eleven
- Fortigate
- IronPort
- Postfix
- Reddoxx
- Trustwave
6. Is your current Exchange organization using a hybrid configuration with Exchange Online?
65% of the Exchange organizations of this questionnaire already run in a hybrid configuration with Exchange Online. Only 35% are (still) not using a hybrid setup.

7. Do you plan to implement a hybrid Exchange configuration or to move to Exchange Online?
Of those who currently do not run a hybrid configuration only 37% plan on implementing Exchange Hybrid or migrate fully to Exchange Online. Staying on-premises is the only option.

8. Until when do you plan to implement a hybrid configuration or go cloud-only?
The majority of the organizations still running only an on-premises Exchange organization plan on implementing Exchange Hybrid or migrating to Exchange Online by the end of 2021. None of the participating organizations has plans scheduled after 2022.

9. Which hybrid model did you choose?
It is no surprise that Classic Full Hybrid is the most adopted hybrid configuration. And, no surprise either, none of the other classic hybrid options is implemented. The modern hybrid approach is implemented but with lesser.

10. What are the reasons for staying 100% on-premises?
The reasons for staying with an on-premises Exchange organization vary. the reasons mentioned are:
- Enclosed environment, external access with BlackBerry UEM, due to public sector data security requirements
- Mailbox data is classified as too sensitive
- Too expensive and low internet bandwidth
- Legal and clients audits
There are still organizations that choose an on-premises Exchange organization in favor of Exchange Online. I wonder if company policies for reducing the carbon footprint might drive the migration of on-premises data center resources to hosted cloud services.
11. Will you implement Exchange Server vNEXT?
Exchange Server vNEXT is in scope for 47% of the organizations. When comparing it with the used Exchange Server version currently in use (~50% Exchange Server 2016) it is an indicator that some companies just skip Exchange Server 2019. Some organizations prefer not to follow the full life-cycle of Exchange Server. s7% of those who do not want to implement Exchange Server vNEXT and want to stay on-premises are single server implementations of Exchange.

Summary
The product Exchange Server is still widely used in on-premises deployments. The reasons vary from legal and compliance requirements, network bandwidth constraints, and the overall costs for Exchange Online. Exchange Server vNEXT is a must-have for nearly 50% of the organizations participating in this questionnaire. There are still older and unsupported versions in productive use. Why this is the case is unanswered in this questionnaire.
Organizations running a hybrid Exchange configuration primarily use a Classic Full Hybrid configuration. This might be due to an early implementation in those days when nothing else was available, or due to requirements using Microsoft Teams with on-premises mailboxes. The adoption of Modern Hybrid shows that the Hybrid Agent approach helps organizations that cannot implement a Classic Full Hybrid.
I leave the results of this questionnaire to your interpretation and look forward to your replies, either to this blog post or by social media on Twitter and LinkedIn. Please use the hashtag #ExchangeQuest2021.
There will be a new Exchange Server questionnaire in early 2022, covering various implementation scenarios in more detail. If you want to see a specific Exchange topic covered in the 2022 questionnaire, just let me know.
Again, thank you all for participating in this questionnaire.