diff --git a/admin_manual/installation/source_installation.rst b/admin_manual/installation/source_installation.rst
index a44b7adab..2eef2567c 100644
--- a/admin_manual/installation/source_installation.rst
+++ b/admin_manual/installation/source_installation.rst
@@ -60,7 +60,6 @@ Required:
 * PHP module XMLWriter
 * PHP module zip
 * PHP module zlib
-* PHP module sodium (for password hashing)
 
 Database connectors (pick the one for your database:)
 
@@ -73,6 +72,7 @@ Database connectors (pick the one for your database:)
 * PHP module bz2 (recommended, required for extraction of apps)
 * PHP module intl (increases language translation performance and fixes sorting
   of non-ASCII characters)
+* PHP module sodium (for Argon2 for password hashing. bcrypt is used as fallback, but if passwords were hashed with Argon2 already and the module is missing, your users can't log in.)
 
 Required for specific apps: