New minimum Outlook for Windows version requirements for Microsoft 365

Unless you are an Enterprise level Microsoft customer, there is no free upgrade from Office 2016 to Office 2022 stand-alone.  Office 2022 (with Outlook 2022) is the only future supported (for four years only) stand-alone version of MS Office supported with Exchange 365 service.   (And hence why this chain of unhappy people is complaining.)    MS Office 2019 is also currently supported, but only through Oct. 2023 (a bit more than year from now at this point, so that is not likely to be a good long term solution for you.)

You real options are all to spend significant money:
1.  Buy new Officer 2022 versions for those Office 2016 versions.  (There is no free upgrade, except for Enterprise customers (where is not really free, its just that upgrades are built into the Enterprise license cost.)
-  To install Office 2022, you can co-install Office 2016 and Office 2022, but I recommend simply uninstalling Office 2016 first, and then installing Office 2022, after you buy the licenses.
2.  You can instead buy Office 365 subscriptions including Outlook Online (aka Outlook 2022 365) for a one year subscription, and then keep paying for one year subscriptions forever.  (That's what Microsoft wants you to do.)
3.  You can dump you current MS Exchange 365 product from Microsoft, and buy a different Exchange product from a different Email/Web provider.  (Earlier posts provide a link to one such summary list, or you can do a web search.  If you pick a different provider, then you should not pick one offering Exchange 365.  That will just result in the same restrictions, from a different provider than Microsoft.   You instead must pick a provider that offers Exchange 2010, 2013, 2016, or 2019 service.   (There are such people on the summary list, or discoverable via Web search.)   Providers offering those products, will work with your existing MS Office 2016 desktop clients without change.   (But then you are changing providers and paying likely more money for email subscription service on Exhcange than MS chargers now.  (So pay more, to a different company.)

None of the solutions are good.  All of them involve being raked over the greed pit by Microsoft, because they have decided that not enough people are leaving their "good enough" fixed non-recurring cost products and switching to the substandard MS Online 365 products (that frankly don't work very well, at least the online part does not) so that you can get the current downloadable Desktop Version of the MS Office suite, on a subscription update service.   MS wants you on that subscription service (recurring renewable money tree for them) and they are going to get you there no matter what.  Now using Exchange service blackmail.

This is of course all under the "cover" of security improvements (to root out spam, because they do that so well) and to protect from web attack (because they do that so well), and get rid of all those security risks they put into the 2016 and 2019 products (that they run with now, and will until 2023).  And all that older stuff, they are not making revenue on (err, I mean its insecure, cough cough, a security risk) and now they are not supporting it anymore, so as to "HELP" you with you decision to move to 365 forever yearly subscription revenue for Microsoft.

Make your own decision for what is right for you.   But none of the "stay with Microsoft" options are affordable and inexpensive.   They are either expensive (stand alone 2022) and short term (only 4 years of support to amoratize the cost, about the same as a subscription cost over 4 years), or they are they yearly cost of the subscription.  Microsoft is taking away your options about when to upgrade, and how much to spend.    That is why I recommend moving off of Microsoft Azure supplied MS Exchange 365 (where they have all these new requirements on your old CLIENTS) and moving to another Exchange product (an older one, from a different provider).    A provider interested in service to its clients, instead of interested only in fleecing its clients with a money grab.

The Exchange 365 product is obviously a solid one.  It works.   The support is pretty terrible, but not often needed.  But this new totally artificial limitation of old clients on an accelerated schedule solely to satisfy "security" concerns that are not real, with the real unexpressed purpose being to accelerate people onto the subscription model who are resisting, and using the level of Exchange 365 is intolerable to me personally.  That is why I am shopping Exchange providers as we speak, and getting pricing information.  I am not going to be dictated to by Microsoft about what of their old products I run, and when I "need" to upgrade them by by that company.    Their approach is ridiculous, and unforgivable.