People migrating from preview versions of Outlook where the email accounts in use were configured as POP3 accounts, get surprised when these accounts are suddenly configured as an Imap account when configuring the account in Outlook ‘2013 or ‘2016. It really has nothing to do with the version of Outlook but more to do with the first screen encountered being the “Auto-Discover” screen where only the email address and password is entered and Outlook proceeds to auto-configure the email account. When this occurs, IMAP will be the default protocol if it’s supported by the email service provider.
If you want the email account to be configured using POP3, it must be configured manually requiring you to know/have the required info for the account such as correct POP3 and SMTP server names, inbound and outbound ports and encryption settings. This information can be obtained by looking at your old Outlook profile settings or must be provided by your email service provider.
The method to retrieve existing email settings that is applicable regardless of Outlook version or operating system is via the Control Panel <Mail> app. When the Mail app is opened, click on the Email Accounts button, highlight the email account of interest and click on the <Change> button. The first screen presented will provide the server name info and clicking on the <More Settings> button will bring you to the other options related to account, most notably under the <Advanced> tab.
The following video steps through the process of manually configuring a POP account