Fix JMAP: Return RFC-3339-conformant UTCDate literals in capabilities: min 0001-01-01T00:00:00Z, max 9999-12-31T23:59:59Z

CHANGELOG.md

@@ -14,6 +14,7 @@ If you are upgrading from v0.16.x, replace the binary (or run `docker pull`). If
 ## Fixed
 - OAuth resource indicators: Accept `imap`, `smtp`, `pop3` and `sieve` as valid resource indicators for OAuth access tokens.
 - PostgreSQL: Incomplete channel binding implementation.
+- JMAP: Return RFC-3339-conformant UTCDate literals in capabilities: min `0001-01-01T00:00:00Z`, max `9999-12-31T23:59:59Z`.
 - Reject invalid duration values (e.g. `1h30m`).
 
 ## [0.16.12] - 2026-07-06

crates/common/src/config/mailstore/capabilities.rs

@@ -7,7 +7,6 @@
 use crate::config::mailstore::jmap::JmapConfig;
 use ahash::AHashSet;
 use calcard::icalendar::ICalendarDuration;
-use chrono::{DateTime, Utc};
 use jmap_proto::{
     object::{email::EmailComparator, file_node::FileNodeComparator},
     request::capability::{
@@ -84,8 +83,28 @@ impl JmapConfig {
             Capability::Calendars,
             Capabilities::Calendar(CalendarCapabilities {
                 max_calendars_per_event: None,
-                min_date_time: UTCDate::from_timestamp(DateTime::<Utc>::MIN_UTC.timestamp()),
+                min_date_time: UTCDate {
-                max_date_time: UTCDate::from_timestamp(DateTime::<Utc>::MAX_UTC.timestamp()),
+                    year: 1,
+                    month: 1,
+                    day: 1,
+                    hour: 0,
+                    minute: 0,
+                    second: 0,
+                    tz_before_gmt: false,
+                    tz_hour: 0,
+                    tz_minute: 0,
+                },
+                max_date_time: UTCDate {
+                    year: 9999,
+                    month: 12,
+                    day: 31,
+                    hour: 23,
+                    minute: 59,
+                    second: 59,
+                    tz_before_gmt: false,
+                    tz_hour: 0,
+                    tz_minute: 0,
+                },
                 max_expanded_query_duration: ICalendarDuration::from_seconds(86400 * 365)
                     .to_string(),
                 max_participants_per_event: bp

tests/src/jmap/principal/get.rs

@@ -105,7 +105,7 @@ pub async fn test(test: &TestServer) {
             "urn:ietf:params:jmap:calendars": {
               "maxCalendarsPerEvent": null,
               "minDateTime": "0001-01-01T00:00:00Z",
-              "maxDateTime": "65534-12-31T23:59:59Z",
+              "maxDateTime": "9999-12-31T23:59:59Z",
               "maxExpandedQueryDuration": "P52W1D",
               "maxParticipantsPerEvent": 20,
               "mayCreateCalendar": true