diff --git a/registry/src/lib.rs b/registry/src/lib.rs
index 2a9a5c7..5140756 100644
--- a/registry/src/lib.rs
+++ b/registry/src/lib.rs
@@ -71,7 +71,7 @@ where
                     timestamp_ns: method
                         .id
                         .get_query_value("timestmap")?
-                        .parse::<i64>()
+                        .parse::<u64>()
                         .ok()?,
                 })
             })
@@ -82,7 +82,9 @@ where
             message: "Identities retrieved".to_string(),
             installations: installations
                 .into_iter()
-                .filter(|i| i.timestamp_ns > start_time_ns)
+                // the only way an i64 cannot fit into a u64 if it's negative, so we can safely set
+                // to 0
+                .filter(|i| i.timestamp_ns > start_time_ns.try_into().unwrap_or(0))
                 .collect(),
         })
     }
diff --git a/xps-types/src/lib.rs b/xps-types/src/lib.rs
index cf17bba..43718a4 100644
--- a/xps-types/src/lib.rs
+++ b/xps-types/src/lib.rs
@@ -117,7 +117,7 @@ pub struct InstallationId {
     // installation id
     pub id: Bytes,
     /// Timestamp in nanoseconds of the block which the operation took place
-    pub timestamp_ns: i64,
+    pub timestamp_ns: u64,
 }
 
 #[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]