DOC-3243: Add on-premises Docker v2 API upgrade notes

- exportpdf_service_url: IMPORTANT note about v2-compatible Docker image
- export-to-pdf-overview: IMPORTANT note with changelog link
- exportpdf_converter_options_combined: Expand NOTE for on-premises

Author: kemister85

modules/ROOT/partials/configuration/exportpdf_converter_options_combined.adoc

@@ -16,7 +16,9 @@ Configures page layout, headers, footers, and other PDF output options. The edit
 Both formats use the same API endpoint. Flat-format options are converted to the nested structure automatically before the request.
 
 [NOTE]
-Requires {productname} 8.4.0 or newer.
+====
+Requires {productname} 8.4.0 or newer. On-premises deployments require a Docker image version that supports the v2 API.
+====
 
 === Flat format
 

modules/ROOT/partials/configuration/exportpdf_service_url.adoc

@@ -5,6 +5,11 @@ The {pluginname} plugin uses an HTML-to-PDF converter service to generate `docum
 
 This option is **required** when configuring the {pluginname} plugin for `on-premise` setups. If you require access to this feature, please link:https://www.tiny.cloud/contact/[contact us]. For detailed instructions on deploying the {pluginname} service server-side component using Docker, refer to the xref:individual-export-to-pdf-on-premises.adoc[on-premises documentation].
 
+[IMPORTANT]
+====
+On-premises deployments require a Docker image version that supports the v2 API (`/v2/convert/html-pdf`). Upgrade to the latest image or a v2-compatible version to use {productname} 8.4.0 or newer with the Export to PDF plugin.
+====
+
 [TIP]
 When using a custom host, set the `exportpdf_service_url` option in your {productname} configuration to match your host. For example, if your custom host is `mycustomhost.com`, set the URL to `https://mycustomhost.com/`.
 

modules/ROOT/partials/individually-licensed-components/export-to-pdf/export-to-pdf-overview.adoc

@@ -3,6 +3,11 @@
 
 The On-Premises version of the {pluginname} Converter is an application that can be installed and run on the customer’s in-house servers and computing infrastructure, including a private cloud. It contains all the features of the {pluginname} Converter available as SaaS.
 
+[IMPORTANT]
+====
+To use {productname} 8.4.0 or newer with the Export to PDF plugin, the on-premises Docker image must support the v2 API (`/v2/convert/html-pdf`). Use the latest image or a v2-compatible version. See the link:https://registry.containers.tiny.cloud/api/changelogs/pdf-converter-tiny[changelog^] for version details.
+====
+
 A valid license key is required in order to install {pluginname} Converter On-Premises. You will also need an access token to access the {companyname} Cloud Docker registry and pull the Docker image. 
 
 To get started, link:https://www.tiny.cloud/contact/[Contact Tiny Support] for a trial license key and Docker access token.