diff --git a/src/opds_dumper.cpp b/src/opds_dumper.cpp
index 8f14e0949..aff73898e 100644
--- a/src/opds_dumper.cpp
+++ b/src/opds_dumper.cpp
@@ -54,7 +54,7 @@ std::string gen_date_str()
 static std::string gen_date_from_yyyy_mm_dd(const std::string& date)
 {
   std::stringstream is;
-  is << date << "T00:00::00Z";
+  is << date << "T00:00:00Z";
   return is.str();
 }
 
diff --git a/test/server.cpp b/test/server.cpp
index 7333c2f2c..68b18fef5 100644
--- a/test/server.cpp
+++ b/test/server.cpp
@@ -616,7 +616,7 @@ std::string maskVariableOPDSFeedData(std::string s)
     "    <title>Charles, Ray</title>\n"                                 \
     "    <summary>Wikipedia articles about Ray Charles</summary>\n"    \
     "    <language>eng</language>\n"                                    \
-    "    <updated>2020-03-31T00:00::00Z</updated>\n"                    \
+    "    <updated>2020-03-31T00:00:00Z</updated>\n"                    \
     "    <name>wikipedia_en_ray_charles</name>\n"                       \
     "    <flavour></flavour>\n"                                         \
     "    <category>jazz</category>\n"                                   \
@@ -640,7 +640,7 @@ std::string maskVariableOPDSFeedData(std::string s)
     "    <title>Ray Charles</title>\n"                                  \
     "    <summary>Wikipedia articles about Ray Charles</summary>\n"     \
     "    <language>eng</language>\n"                                    \
-    "    <updated>2020-03-31T00:00::00Z</updated>\n"                    \
+    "    <updated>2020-03-31T00:00:00Z</updated>\n"                    \
     "    <name>wikipedia_en_ray_charles</name>\n"                       \
     "    <flavour></flavour>\n"                                         \
     "    <category>wikipedia</category>\n"                              \
@@ -664,7 +664,7 @@ std::string maskVariableOPDSFeedData(std::string s)
     "    <title>Ray (uncategorized) Charles</title>\n"                  \
     "    <summary>No category is assigned to this library entry.</summary>\n" \
     "    <language>eng</language>\n"                                    \
-    "    <updated>2020-03-31T00:00::00Z</updated>\n"                    \
+    "    <updated>2020-03-31T00:00:00Z</updated>\n"                    \
     "    <name>wikipedia_en_ray_charles</name>\n"                       \
     "    <flavour></flavour>\n"                                         \
     "    <category></category>\n"                                \