diff --git a/docs/Gemfile.lock b/docs/Gemfile.lock
index f05393e..229849c 100644
--- a/docs/Gemfile.lock
+++ b/docs/Gemfile.lock
@@ -98,7 +98,7 @@ GEM
       gemoji (~> 2.0)
       html-pipeline (~> 2.2)
       jekyll (>= 3.0)
-    json (1.8.3)
+    json (2.1.0)
     kramdown (1.11.1)
     liquid (3.0.6)
     listen (3.0.6)
diff --git a/docs/_data/promo.yml b/docs/_data/promo.yml
index 0d09b3a..92efb79 100644
--- a/docs/_data/promo.yml
+++ b/docs/_data/promo.yml
@@ -13,5 +13,5 @@
     href: docs/quick_start.html#python-api
     text: Get started in Python
   - type: button
-    href: static/prophet_paper_preprint.pdf
+    href: https://peerj.com/preprints/3190/
     text: Read the paper