I have a Mac mini & a Mac laptop & an Android smartphone & I want to get an iPad. iMessage is not compatible with Android. I want to be able to send & receive text messages to/from iOS, OSX, Android & Windows. Apple Mail & Apple Messages use IMAP. I've read recent Verizon forums that state that Verizon doesn't support IMAP & has no intention to support it. Is that true?
Then how do I send & receive e-mails to/from iOS, OSX, Android & Windows?
Welcome to the forums. You're talking to other customers here.
As far as I know, Verizon's email does not support IMAP. This does not preclude you from using IMAP with other email services such as gmail, Apple's mail or Microsoft's mail. You just can't use IMAP with a verizon.net email address.
If you're asking about Verizon.net email, know that we uses have no information about if or when Verizon might add IMAP support.
POP can be used from multiple devices, but it does not support synchronization of the message database. If POP clients are configured to delete received email from the server, only the first POP client to access the email will be able to see it. If the clients are configured to leave email on the server, changes in read status and deletions will not propagate to the other clients. In short, POP is really bad for accessing email from multiple devices.
If you want multi-device synchronization with verizon.net (and who doesn't these days), then you need to use an email system with support for IMAP or Microsoft Exchange. Apple, gmail and outlook.com are all good options. They can be setup to pull email from Verizon. This way, you can use a modern email server.
I'm pretty sure that I was able to download my Verizon e-mails onto my Mac mini.
I'm guessing that IMAP will send & receive POP3 e-mails but not the other way around.
I considered Skype because it can send & receive e-mails but it would be wrong of me to insist that my friends & relatives install & use Skype.
So, since iMessage is incompatible with Android, the only solution that I can come up with is to use e-mail across devices.
Ah, the question you're asking has nothing to do with POP or IMAP. You appear to be looking for a cross platform text or instant messaging system.
As you've noted, iMessage plays on Apple products only. Simple texting works across any phone type device, but doens't reach non-phone devices such as WiFi only tablets and computers. email is not instant messaging and may not get the attention from your friends and family that you desire.
There are several cross platform instant messaging apps. Skype and Google Hangouts are a couple of popular ones. Facebook has one as well ("messenger"). Pick one that you think will be used by the folks you want to reach.