Use Guillaume's suggested versioning scheme, migration-guides/3.16

_config.yml

@@ -80,7 +80,7 @@ collections:
     permalink: /version/:path
   migrations:
     output: true
-    permalink: /migration/:path
+    permalink: /migration-guides/:version
 
 # Exclude from processing.
 # The following items will not be processed, by default. Create a custom list
@@ -131,6 +131,8 @@ defaults:
     values:
       layout: migration-guide
       toc: true
+      version_regex: "Migration-Guide-"
+      # permalink needs be defined above, with the collection definition
   -
     scope:
       type: redirects

_layouts/migration-guide.html

@@ -21,7 +21,7 @@
 <section class="full-width-version-bg flexfilterbar guides">
   <div class="guideflexcontainer">
     <div class="docslink">
-      <a class="returnlink" href="{{site.baseurl}}/migrations/"> Back to Migration Guides</a>
+      <a class="returnlink" href="{{site.baseurl}}/migration-guides/"> Back to Migration Guides</a>
     </div>
    </div>
 </section>

_plugins/version_permalink.rb

@@ -0,0 +1,38 @@
+module VersionPermalink
+  class VersionPermalink < Jekyll::Generator
+    safe true
+    priority :low
+
+    def generate(site)
+      # fill in version information from the filename
+      collection = site.collections["migrations"]
+      collection.docs.each { |doc|
+        data = doc.data
+        reg_str = data["version_regex"]
+        repl_str = ""
+        re = Regexp.new reg_str
+
+        # This will be returned
+        puts "got regex"
+        version = data["slug"].gsub re, repl_str
+        puts doc.data["version_regex"]
+        doc.data.merge!('version' => version)
+
+      }
+    end
+
+    Jekyll::Hooks.register :migrations, :pre_render do |doc|
+      begin
+        # check if jekyll can resolve the url template
+        doc.url
+      rescue NoMethodError => error
+        begin
+          def doc.url_template
+            custom_permalink_placeholders = ["version"]
+            @custom_url_template ||= custom_permalink_placeholders.inject(collection.url_template) { |o, m| o.sub ":" + m, version.to_s }
+          end
+        end
+      end
+    end
+  end
+end

migration-guides.html

@@ -0,0 +1,13 @@
+---
+layout: base
+---
+
+<h1>Migration Guides</h1>
+
+{% assign doclist = site.migrations   %}
+    <ul>
+       {% for doc in doclist %}
+        <li><a href="{{ site.baseurl }}{{ doc.url }}">{{ doc.version }}</a></li>
+        {% endfor %}
+    </ul>
+