Revert ACMEv2 default (#5819)

* Revert "document default is ACMEv2 (#5818)"

This reverts commit 2c502e6.

* Revert "Update default to ACMEv2 server (#5722)"

This reverts commit 4d706ac.

certbot/constants.py

@@ -84,7 +84,7 @@
     config_dir="/etc/letsencrypt",
     work_dir="/var/lib/letsencrypt",
     logs_dir="/var/log/letsencrypt",
-    server="https://acme-v02.api.letsencrypt.org/directory",
+    server="https://acme-v01.api.letsencrypt.org/directory",
 
     # Plugins parsers
     configurator=None,

docs/using.rst

@@ -871,16 +871,24 @@ Example usage for DNS-01 (Cloudflare API v4) (for example purposes only, do not
 Changing the ACME Server
 ========================
 
-By default, Certbot uses Let's Encrypt's ACMEv2 production server at
-https://acme-v02.api.letsencrypt.org/. You can tell Certbot to use a
+By default, Certbot uses Let's Encrypt's initial production server at
+https://acme-v01.api.letsencrypt.org/. You can tell Certbot to use a
 different CA by providing ``--server`` on the command line or in a
 :ref:`configuration file <config-file>` with the URL of the server's
 ACME directory. For example, if you would like to use Let's Encrypt's
-initial ACMEv1 server, you would add ``--server
-https://acme-v01.api.letsencrypt.org/directory`` to the command line.
+new ACMEv2 server, you would add ``--server
+https://acme-v02.api.letsencrypt.org/directory`` to the command line.
 Certbot will automatically select which version of the ACME protocol to
 use based on the contents served at the provided URL.
 
+If you use ``--server`` to specify an ACME CA that implements a newer
+version of the spec, you may be able to obtain a certificate for a
+wildcard domain. Some CAs (such as Let's Encrypt) require that domain
+validation for wildcard domains must be done through modifications to
+DNS records which means that the dns-01_ challenge type must be used. To
+see a list of Certbot plugins that support this challenge type and how
+to use them, see plugins_.
+
 Lock Files
 ==========