docs: improve upgrade path guidance (#16925)

website/content/docs/upgrading/instructions/index.mdx

@@ -10,45 +10,43 @@ description: >-
 
 This document is intended to help users who find themselves many versions behind to upgrade safely.
 
-## Upgrade Path
+## General Upgrade Path
 
-Our recommended upgrade path is to move through the following sequence of versions:
+Each upgrade should jump at most 2 major versions, except where
+[dedicated instructions](#dedicated-instructions-for-specific-upgrade-paths)
+are provided for a larger jump between specific versions.
+If your upgrade path has no applicable [dedicated instructions](#dedicated-instructions-for-specific-upgrade-paths),
+review the [version-specific upgrade details](/consul/docs/upgrading/upgrade-specific)
+to plan your upgrade, starting from the next version and working
+upwards to your target version.
 
-- 0.8.5 (final 0.8.x)
+For example, to upgrade from Consul 1.12 to Consul 1.15:
-- 1.2.4 (final 1.2.x)
-- 1.6.10 (final 1.6.x)
-- 1.8.19 (final 1.8.x)
-- 1.10.12 (final 1.10.x)
-- Latest 1.12.x
-- Latest 1.13.x ([at least 1.13.1](/consul/docs/upgrading/upgrade-specific#service-mesh-compatibility))
-- Latest 1.14.x
 
-## Getting Started
+1. Upgrade to Consul 1.14 as an intermediate step.
+   To plan, review the upgrade details for
+   [1.13](/consul/docs/upgrading/upgrade-specific#consul-1-13-x) and
+   [1.14](/consul/docs/upgrading/upgrade-specific#consul-1-14-x).
+1. Upgrade to Consul 1.15.
+   To plan, review the upgrade details for
+   [1.15](/consul/docs/upgrading/upgrade-specific#consul-1-15-x).
 
-To get instructions for your upgrade, follow the instructions given below for
+## Dedicated Instructions for Specific Upgrade Paths
-your _currently installed_ release series until you are on the latest current version.
-The upgrade guides will mention notable changes and link to relevant changelogs –
-we recommend reviewing the changelog for versions between the one you are on and the
-one you are upgrading to at each step to familiarize yourself with changes.
 
-Select your _currently installed_ release series:
+The following table provides links to dedicated instructions
-- 1.13.x: work upwards from [1.14 upgrade notes](/consul/docs/upgrading/upgrade-specific#consul-1-14-x)
+for directly upgrading from a version in the starting range
-- 1.12.x: work upwards from [1.13 upgrade notes](/consul/docs/upgrading/upgrade-specific#consul-1-13-x)
+to a destination version.
-- 1.11.x: work upwards from [1.12 upgrade notes](/consul/docs/upgrading/upgrade-specific#consul-1-12-0)
-- 1.10.x: work upwards from [1.11 upgrade notes](/consul/docs/upgrading/upgrade-specific#consul-1-11-0)
-- [1.9.x](/consul/docs/upgrading/instructions/upgrade-to-1-10-x)
-- [1.8.x](/consul/docs/upgrading/instructions/upgrade-to-1-10-x)
-- [1.7.x](/consul/docs/upgrading/instructions/upgrade-to-1-8-x)
-- [1.6.x](/consul/docs/upgrading/instructions/upgrade-to-1-8-x)
-- [1.5.x](/consul/docs/upgrading/instructions/upgrade-to-1-6-x)
-- [1.4.x](/consul/docs/upgrading/instructions/upgrade-to-1-6-x)
-- [1.3.x](/consul/docs/upgrading/instructions/upgrade-to-1-6-x)
-- [1.2.x](/consul/docs/upgrading/instructions/upgrade-to-1-6-x)
-- [1.1.x](/consul/docs/upgrading/instructions/upgrade-to-1-2-x)
-- [1.0.x](/consul/docs/upgrading/instructions/upgrade-to-1-2-x)
-- [0.9.x](/consul/docs/upgrading/instructions/upgrade-to-1-2-x)
-- [0.8.x](/consul/docs/upgrading/instructions/upgrade-to-1-2-x)
 
-If you are using <= 0.7.x, please contact support for assistance:
+| Starting Version Range | Destination Version | Upgrade Instructions |
-- OSS users without paid support plans can request help in our [Community Forum](https://discuss.hashicorp.com/c/consul/29)
+| ---------------------- | ------------------- | -------------------- |
-- Enterprise and OSS users with paid support plans can contact [HashiCorp Support](https://support.hashicorp.com/)
+| 1.8.0 - 1.9.17         | 1.10.12             | Refer to [upgrading to latest 1.10.x](/consul/docs/upgrading/instructions/upgrade-to-1-10-x) |
+| 1.6.9 - 1.8.18         | 1.8.19              | Refer to [upgrading to latest 1.8.x](/consul/docs/upgrading/instructions/upgrade-to-1-8-x) |
+| 1.2.4 - 1.6.9          | 1.6.10              | Refer to [upgrading to latest 1.6.x](/consul/docs/upgrading/instructions/upgrade-to-1-6-x) |
+| 0.8.5 - 1.2.3          | 1.2.4               | Refer to [upgrading to latest 1.2.x](/consul/docs/upgrading/instructions/upgrade-to-1-2-x) |
+
+For example, to upgrade from Consul 1.3.1 to latest 1.12:
+1. Upgrade to Consul 1.6.10 using the dedicated instructions.
+1. Upgrade to Consul 1.8.19 using the dedicated instructions.
+1. Upgrade to Consul 1.10.12 using the dedicated instructions.
+1. Upgrade to latest Consul 1.12.x after consulting the
+   [version-specific upgrade details](/consul/docs/upgrading/upgrade-specific)
+   for 1.11 and 1.12.

website/content/docs/upgrading/upgrade-specific.mdx

@@ -515,6 +515,14 @@ to Consul 1.11.11 or later to avoid the breaking nature of that change.
 
 ### Licensing Changes <EnterpriseAlert inline />
 
+You can only upgrade to Consul Enterprise 1.10 from the following Enterprise versions:
+- 1.8 release series: 1.8.13+
+- 1.9 release series: 1.9.7+
+
+Other versions of Consul Enterprise are not forward compatible with v1.10 and will
+cause issues during the upgrade that could result in agents failing to start due to
+[changes in the way we manage licenses](/consul/docs/enterprise/license/faq).
+
 Consul Enterprise 1.10 has removed temporary licensing capabilities from the binaries
 found on https://releases.hashicorp.com. Servers will no longer load a license previously
 set through the CLI or API. Instead the license must be present in the server's configuration