diff --git a/config/filters/index.js b/config/filters/index.js
index 4196aec9..1ffbe5c3 100644
--- a/config/filters/index.js
+++ b/config/filters/index.js
@@ -70,7 +70,7 @@ export default {
       })
       .split(',')[0]
   },
-  isoDateOnly: (date) => {
+  isoDateOnly: (date, separator) => {
     let d = new Date(date)
     let month = '' + (d.getMonth() + 1)
     let day = '' + d.getDate()
@@ -79,7 +79,7 @@ export default {
     if (month.length < 2) month = '0' + month
     if (day.length < 2) day = '0' + day
 
-    return [month, day, year].join('.')
+    return [year, month, day].join(separator)
   },
   stringToDate: (string) => {
     if (!string) return
diff --git a/package.json b/package.json
index 75d82c41..7c069c97 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "coryd.dev",
-  "version": "6.5.13",
+  "version": "6.5.14",
   "description": "The source for my personal site. Built using 11ty and hosted on Netlify.",
   "type": "module",
   "scripts": {
diff --git a/src/_includes/base.liquid b/src/_includes/base.liquid
index 493def88..7a9e0d61 100644
--- a/src/_includes/base.liquid
+++ b/src/_includes/base.liquid
@@ -61,7 +61,7 @@
             "@type": "Person",
             "name": "{{ meta.author }}"
           },
-          "datePublished": "{{ page.date | isoDateOnly }}"
+          "datePublished": "{{ page.date | isoDateOnly: '.' }}"
         }
       </script>
       {% else %}
diff --git a/src/pages/sitemap.liquid b/src/pages/sitemap.liquid
index a20e66c2..ab9987f6 100644
--- a/src/pages/sitemap.liquid
+++ b/src/pages/sitemap.liquid
@@ -8,7 +8,7 @@ eleventyExcludeFromCollections: true
     {% if not page.data.draft %}
       <url>
         <loc>{{ meta.url }}{{ page.url }}</loc>
-        <lastmod>{{ page.date | isoDateOnly }}</lastmod>
+        <lastmod>{{ page.date | isoDateOnly: '-' }}</lastmod>
         <changefreq>{%- if page.data.changeFreq -%}{{ page.data.changeFreq }}{%- else -%}monthly{%- endif -%}</changefreq>
         <priority>{%- if page.data.priority -%}{{ page.data.priority }}{%- else -%}0.5{%- endif %}</priority>
       </url>
diff --git a/src/posts/2023/webmentions-in-eleventy.md b/src/posts/2023/webmentions-in-eleventy.md
index b63f11b2..12f9f9d8 100644
--- a/src/posts/2023/webmentions-in-eleventy.md
+++ b/src/posts/2023/webmentions-in-eleventy.md
@@ -121,7 +121,7 @@ When the build runs, it renders any mentions of a given post via a [liquid.js](h
                 />
                 <div class="ml-3">
                     <p class="text-sm group-hover:text-blue-500 dark:group-hover:text-blue-300">{{mention.content.text}}</p>
-                    <p class="mt-1 text-xs group-hover:text-blue-500 dark:group-hover:text-blue-300">{{mention.published | isoDateOnly}}</p>
+                    <p class="mt-1 text-xs group-hover:text-blue-500 dark:group-hover:text-blue-300">{{mention.published | isoDateOnly: '.' }}</p>
                 </div>
             </a>
         </div>