diff --git a/security/acme-client/pkg-descr b/security/acme-client/pkg-descr
index 0f08eea38..b6dc6e05e 100644
--- a/security/acme-client/pkg-descr
+++ b/security/acme-client/pkg-descr
@@ -8,6 +8,15 @@ WWW: https://github.com/acmesh-official/acme.sh
 Plugin Changelog
 ================
 
+3.0
+
+Added:
+* add support for new ACME CA's: buypass, buypass_test, sslcom, zerossl (#2361)
+
+Changed:
+* rename "Let's Encrypt Environment" to "ACME CA" (#2361)
+* preserve old LE accounts/certs by adding a compatibility layer (#2361)
+
 2.6
 
 Added:
diff --git a/security/acme-client/src/opnsense/mvc/app/controllers/OPNsense/AcmeClient/forms/settings.xml b/security/acme-client/src/opnsense/mvc/app/controllers/OPNsense/AcmeClient/forms/settings.xml
index ad0247d9e..b72241e64 100644
--- a/security/acme-client/src/opnsense/mvc/app/controllers/OPNsense/AcmeClient/forms/settings.xml
+++ b/security/acme-client/src/opnsense/mvc/app/controllers/OPNsense/AcmeClient/forms/settings.xml
@@ -12,10 +12,10 @@
         <help><![CDATA[Enable automatic renewal for certificates to prevent expiration. This will add a cron job to the system. You may want to customize the cron job schedule to your needs, because re-issueing a certificate may lead to a short downtime, depending on the selected challenge type and service.]]></help>
     </field>
     <field>
-        <id>acmeclient.settings.environment</id>
-        <label>Let's Encrypt Environment</label>
+        <id>acmeclient.settings.ca</id>
+        <label>ACME CA</label>
         <type>dropdown</type>
-        <help><![CDATA[Choose Let's Encrypts staging environment when using it for the first time or while testing new challenge types. The staging environment offers <a href="https://letsencrypt.org/docs/staging-environment/">relaxed rate limits</a>.<br/><div class="text-info"><b>NOTE:</b>Certificates signed by the staging environment are NOT valid. You need to forcefully re-sign (or delete and re-create) them after switching from staging to production environment.</div>]]></help>
+        <help><![CDATA[The ACME CA that should be used to issue or renew certificates. Note that some of them offer paid services and may require a subscription. Check the <a href="https://github.com/acmesh-official/acme.sh/wiki/Server">acme.sh documentation</a> for a list of supported CAs.]]></help>
     </field>
     <field>
         <id>acmeclient.settings.haproxyIntegration</id>
diff --git a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeAccount.php b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeAccount.php
index dc8f0d33f..5aa9e2ab2 100644
--- a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeAccount.php
+++ b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeAccount.php
@@ -1,7 +1,7 @@
 <?php
 
 /*
- * Copyright (C) 2020 Frank Wall
+ * Copyright (C) 2020-2021 Frank Wall
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,8 +53,8 @@ class LeAccount extends LeCommon
         // Set log level
         $this->setLoglevel();
 
-        // Set Let's Encrypt environment
-        $this->setEnvironment();
+        // Set ACME CA
+        $this->setCa();
 
         // Store acme filenames
         $this->acme_args[] = LeUtils::execSafe('--home %s', self::ACME_HOME_DIR);
@@ -66,7 +66,7 @@ class LeAccount extends LeCommon
     public function generateKey()
     {
         // Collect account information
-        $account_conf_dir = self::ACME_BASE_ACCOUNT_DIR . '/' . (string)$this->config->id . '_' . $this->environment;
+        $account_conf_dir = self::ACME_BASE_ACCOUNT_DIR . '/' . (string)$this->config->id . '_' . $this->ca_compat;
         $account_conf_file = $account_conf_dir . '/account.conf';
         $account_key_file = $account_conf_dir . '/account.key';
         $account_json_file = $account_conf_dir . '/account.json';
diff --git a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeAutomation/Base.php b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeAutomation/Base.php
index b6a07a727..67ce269f2 100644
--- a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeAutomation/Base.php
+++ b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeAutomation/Base.php
@@ -1,7 +1,7 @@
 <?php
 
 /*
- * Copyright (C) 2020 Frank Wall
+ * Copyright (C) 2020-2021 Frank Wall
  * Copyright (C) 2018 Deciso B.V.
  * Copyright (C) 2018 Franco Fichtner <franco@opnsense.org>
  * All rights reserved.
@@ -63,8 +63,8 @@ abstract class Base extends \OPNsense\AcmeClient\LeCommon
         // Set log level
         $this->setLoglevel();
 
-        // Set Let's Encrypt environment
-        $this->setEnvironment();
+        // Set ACME CA
+        $this->setCa();
 
         return true;
     }
diff --git a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeCertificate.php b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeCertificate.php
index 97b4d2364..bc84d49b3 100644
--- a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeCertificate.php
+++ b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeCertificate.php
@@ -74,8 +74,8 @@ class LeCertificate extends LeCommon
         // Set log level
         $this->setLoglevel();
 
-        // Set Let's Encrypt environment
-        $this->setEnvironment();
+        // Set ACME CA
+        $this->setCa();
 
         // Handle special key types
         if ($this->config->keyLength == 'key_ec256' || $this->config->keyLength == 'key_ec384') {
@@ -528,7 +528,7 @@ class LeCertificate extends LeCommon
         LeUtils::log('revoking certificate: ' . (string)$this->config->name);
 
         // Collect account information
-        $account_conf_dir = self::ACME_BASE_ACCOUNT_DIR . '/' . $this->account_id . '_' . $this->environment;
+        $account_conf_dir = self::ACME_BASE_ACCOUNT_DIR . '/' . $this->account_id . '_' . $this->ca_compat;
         $account_conf_file = $account_conf_dir . '/account.conf';
 
         // Preparation to run acme client
diff --git a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeCommon.php b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeCommon.php
index 151445d0c..422a82508 100644
--- a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeCommon.php
+++ b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeCommon.php
@@ -83,7 +83,8 @@ abstract class LeCommon
     protected $cron;                # Run from cron job
     protected $config;              # AcmeClient config object
     protected $debug;               # Debug logging (bool)
-    protected $environment;         # Let's Encrypt environment (uses shortnames)
+    protected $ca;                  # ACME CA
+    protected $ca_compat;           # ACME CA for compat with old LE CA names
     protected $force;               # Force operation
     protected $model;               # AcmeClient model object
     protected $uuid;                # AcmeClient config object uuid
@@ -136,12 +137,29 @@ abstract class LeCommon
     }
 
     /**
-     * set Let's Encrypt environment for acme.sh
+     * set ACME CA for acme.sh
      */
-    public function setEnvironment()
+    public function setCa()
     {
-        $this->environment = (string)$this->model->getNodeByReference('settings.environment');
-        $this->acme_args[] = $this->environment == 'stg' ? '--staging' : null;
+        $this->ca = (string)$this->model->getNodeByReference('settings.ca');
+        $this->acme_args[] = LeUtils::execSafe('--server %s', $this->ca);
+
+        // Evaluate how the CA should be represented in filenames.
+        // This is a compatibility layer. It ensures that old files that
+        // were generated for the Let's Encrypt Production/Staging CA
+        // can still be used.
+        switch ($this->ca) {
+            case 'letsencrypt':
+                $ca_compat = 'prod';
+                break;
+            case 'letsencrypt_test':
+                $ca_compat = 'stg';
+                break;
+            default:
+                $ca_compat = $this->ca;
+                break;
+        }
+        $this->ca_compat = $ca_compat;
     }
 
     /**
diff --git a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeValidation/Base.php b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeValidation/Base.php
index a69443228..0c2dcb317 100644
--- a/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeValidation/Base.php
+++ b/security/acme-client/src/opnsense/mvc/app/library/OPNsense/AcmeClient/LeValidation/Base.php
@@ -1,7 +1,7 @@
 <?php
 
 /*
- * Copyright (C) 2020 Frank Wall
+ * Copyright (C) 2020-2021 Frank Wall
  * Copyright (C) 2018 Deciso B.V.
  * Copyright (C) 2018 Franco Fichtner <franco@opnsense.org>
  * All rights reserved.
@@ -73,8 +73,8 @@ abstract class Base extends \OPNsense\AcmeClient\LeCommon
         // Set log level
         $this->setLoglevel();
 
-        // Set Let's Encrypt environment
-        $this->setEnvironment();
+        // Set ACME CA
+        $this->setCa();
 
         // Store acme hook
         switch ((string)$this->config->method) {
@@ -141,8 +141,8 @@ abstract class Base extends \OPNsense\AcmeClient\LeCommon
             }
         }
 
-        // Use individual account config for each environment
-        $account_conf_dir = self::ACME_BASE_ACCOUNT_DIR . '/' . $this->account_id . '_' . $this->environment;
+        // Use individual account config for each CA
+        $account_conf_dir = self::ACME_BASE_ACCOUNT_DIR . '/' . $this->account_id . '_' . $this->ca_compat;
         $account_conf_file = $account_conf_dir . '/account.conf';
 
         // Preparation to run acme client
diff --git a/security/acme-client/src/opnsense/mvc/app/models/OPNsense/AcmeClient/AcmeClient.xml b/security/acme-client/src/opnsense/mvc/app/models/OPNsense/AcmeClient/AcmeClient.xml
index 29a998e7b..a105ce598 100644
--- a/security/acme-client/src/opnsense/mvc/app/models/OPNsense/AcmeClient/AcmeClient.xml
+++ b/security/acme-client/src/opnsense/mvc/app/models/OPNsense/AcmeClient/AcmeClient.xml
@@ -1,6 +1,6 @@
 <model>
     <mount>//OPNsense/AcmeClient</mount>
-    <version>2.1.0</version>
+    <version>3.0.0</version>
     <description>A secure Let's Encrypt plugin</description>
     <items>
         <settings>
@@ -27,13 +27,25 @@
                 <Required>N</Required>
             </UpdateCron>
             <environment type="OptionField">
-                <Required>Y</Required>
+                <Required>N</Required>
                 <default>prod</default>
                 <OptionValues>
                     <prod>Production Environment [default]</prod>
                     <stg>Staging Environment</stg>
                 </OptionValues>
             </environment>
+            <ca type="OptionField">
+                <Required>Y</Required>
+                <default></default>
+                <OptionValues>
+                    <buypass>Buypass</buypass>
+                    <buypass_test>Buypass Test CA</buypass_test>
+                    <letsencrypt>Let's Encrypt [default]</letsencrypt>
+                    <letsencrypt_test>Let's Encrypt Test CA</letsencrypt_test>
+                    <sslcom>SSL.com</sslcom>
+                    <zerossl>ZeroSSL</zerossl>
+                </OptionValues>
+            </ca>
             <challengePort type="IntegerField">
                 <default>43580</default>
                 <MinimumValue>1024</MinimumValue>
diff --git a/security/acme-client/src/opnsense/mvc/app/models/OPNsense/AcmeClient/Migrations/M3_0_0.php b/security/acme-client/src/opnsense/mvc/app/models/OPNsense/AcmeClient/Migrations/M3_0_0.php
new file mode 100644
index 000000000..a2f0262e5
--- /dev/null
+++ b/security/acme-client/src/opnsense/mvc/app/models/OPNsense/AcmeClient/Migrations/M3_0_0.php
@@ -0,0 +1,54 @@
+<?php
+
+/**
+ *    Copyright (C) 2021 Frank Wall
+ *
+ *    All rights reserved.
+ *
+ *    Redistribution and use in source and binary forms, with or without
+ *    modification, are permitted provided that the following conditions are met:
+ *
+ *    1. Redistributions of source code must retain the above copyright notice,
+ *       this list of conditions and the following disclaimer.
+ *
+ *    2. Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *
+ *    THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ *    INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
+ *    AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ *    AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
+ *    OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *    SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ *    INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *    CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ *    ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *    POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+namespace OPNsense\AcmeClient\Migrations;
+
+use OPNsense\Base\BaseModelMigration;
+
+class M3_0_0 extends BaseModelMigration
+{
+    public function run($model)
+    {
+        // Get old LE environment and map to new value
+        $env = (string)$model->settings->environment;
+        switch ($env) {
+            case 'prod':
+                $new_ca = 'letsencrypt';
+                break;
+            case 'stg':
+                $new_ca = 'letsencrypt_test';
+                break;
+        }
+
+        // Set new CA
+        $model->settings->ca = $new_ca;
+        $model->settings->environment = null; // clear old value
+    }
+}
diff --git a/security/acme-client/src/opnsense/mvc/app/views/OPNsense/AcmeClient/settings.volt b/security/acme-client/src/opnsense/mvc/app/views/OPNsense/AcmeClient/settings.volt
index 2d1b034e7..a77378f43 100644
--- a/security/acme-client/src/opnsense/mvc/app/views/OPNsense/AcmeClient/settings.volt
+++ b/security/acme-client/src/opnsense/mvc/app/views/OPNsense/AcmeClient/settings.volt
@@ -1,6 +1,6 @@
 {#
 
-Copyright (C) 2017-2019 Frank Wall
+Copyright (C) 2017-2021 Frank Wall
 OPNsense® is Copyright © 2014-2015 by Deciso B.V.
 All rights reserved.
 
@@ -247,7 +247,7 @@ POSSIBILITY OF SUCH DAMAGE.
         <br/>
     </div>
     <div class="col-md-12">
-        <b>{{ lang._("Please read the official %sLet's Encrypt documentation%s before using this plugin. Otherwise you will easily hit its %srate limits%s and thus all your attempts to issue a certificate will fail.") | format('<a href="https://letsencrypt.org/how-it-works/">', '</a>', '<a href="https://letsencrypt.org/docs/rate-limits/">', '</a>') }}</b>{{ lang._("Please use Let's Encrypt's %sstaging servers%s when using this plugin for the first time or while testing a new challenge type. You will have to reissue your certificates when switching from staging to production servers to get valid certificates.") | format('<a href="https://letsencrypt.org/docs/staging-environment/">', '</a>') }}
+        <b>{{ lang._("Please read the official %sLet's Encrypt documentation%s before using this plugin. It should give you a good overview about how the various ACME CAs work, so you do not hit their %srate limits%s and avoid common misconfigurations, which would let all your attempts to issue a certificate fail.") | format('<a href="https://letsencrypt.org/how-it-works/">', '</a>', '<a href="https://letsencrypt.org/docs/rate-limits/">', '</a>') }}</b>{{ lang._("Please use a %stest CA%s when using this plugin for the first time or while testing a new challenge type. Note that you will have to reissue your certificates when switching from a test to a production CA to get valid certificates.") | format('<a href="https://letsencrypt.org/docs/staging-environment/">', '</a>') }}
         <br/>
         {{ lang._('Please use the %sissue tracker%s to report bugs or request new features.') | format('<a href="https://github.com/opnsense/plugins/issues">', '</a>') }}
         <br/>