@@ -123,34 +123,6 @@ cfg = config.services.mycal;
             settingsFormat = pkgs.formats.toml { };
 
             inherit (lib) mkEnableOption mkOption mkIf types;
-
-            calendarOptionType = types.submodule {
-              options = {
-                file = mkOption {
-                  type = with types; nullOr str;
-                  default = "";
-                  example = "/path/to/calendar/file";
-                  description = ''
-                    Path to the calendar file. Preferred over URL.
-                  '';
-                };
-                url = mkOption {
-                  type = with types; nullOr str;
-                  default = "";
-                  example = "https://example.com/calendar.ics";
-                  description = ''
-                    URL to the calendar file.
-                  '';
-                };
-                all_tentative = mkOption {
-                  type = types.bool;
-                  default = false;
-                  description = ''
-                    Whether all events from this calendar should be marked as tentative.
-                  '';
-                };
-              };
-            };
           in
           {
             options.services.mycal = {
@@ -204,25 +176,39 @@ Default timezone for the calendar.
                       '';
                     };
 
-                    calendar = mkOption {
-                      default = { };
-                      description = ''
-                        Configuration for a single calendar. Either a file or a URL must be provided.
-                        This option is kept for backward compatibility. Using the calendars option
-                        is recommended for new configurations.
-
-                        Note: This option is deprecated and will be removed in a future release.
-                      '';
-                      type = calendarOptionType;
-                    };
-
                     calendars = mkOption {
                       default = [ ];
                       description = ''
                         Configuration for multiple calendars. This option will be appended to the
                         singular calendar option if both are specified.
                       '';
-                      type = types.listOf calendarOptionType;
+                      type = types.listOf (types.submodule {
+                        options = {
+                          file = mkOption {
+                            type = with types; nullOr str;
+                            default = null;
+                            example = "/path/to/calendar/file";
+                            description = ''
+                              Path to the calendar file. Preferred over URL.
+                            '';
+                          };
+                          url = mkOption {
+                            type = with types; nullOr str;
+                            default = null;
+                            example = "https://example.com/calendar.ics";
+                            description = ''
+                              URL to the calendar file.
+                            '';
+                          };
+                          all_tentative = mkOption {
+                            type = types.bool;
+                            default = false;
+                            description = ''
+                              Whether all events from this calendar should be marked as tentative.
+                            '';
+                          };
+                        };
+                      });
                     };
 
                     email = mkOption {
@@ -243,16 +229,10 @@ # Validate configuration
               assertions = [
                 {
                   assertion = with cfg.settings;
-                    (calendars != [ ] && builtins.any (cal: cal.file != "" || cal.url != "") calendars) ||
-                      (calendar.file != "" || calendar.url != "");
-                  message = "At least one calendar must be configured with either a file or URL in either settings.calendar or settings.calendars";
+                    (calendars != [ ] && builtins.any (cal: cal.file != "" || cal.url != "") calendars);
+                  message = "At least one calendar must be configured with either a file or URL in settings.calendars";
                 }
               ];
-
-              # Issue deprecation warning if the calendar option is used
-              warnings = lib.optional
-                (cfg.settings.calendar.file != "" || cfg.settings.calendar.url != "")
-                "The settings.calendar option is deprecated and will be removed in a future release. Please use the settings.calendars option instead.";
 
               systemd.services.mycal = {
                 description = "Mycal Calendar Service";

@@ -24,8 +24,7 @@ class Config(TomlDataClassIO):
     name: str
     email: str
     timezone: str
-    calendar: typing.Optional[CalendarConfig] = None  # Keep for backward compatibility
-    calendars: typing.List[CalendarConfig] = field(default_factory=list)  # New field for multiple calendars
+    calendars: typing.List[CalendarConfig] = field(default_factory=list)
 
 def load_config(file_path):
     with open(file_path, "r") as fr:
@@ -125,18 +124,9 @@ busy.add('dtstart', start_date.astimezone(tz=utc))
     busy.add('dtend', end_date.astimezone(tz=utc))
 
     try:
-        calendars_to_process = []
         busy_periods = {}
 
-        # For backward compatibility
-        if config.calendar is not None and (config.calendar['file'] != "" or config.calendar['url'] != ""):
-            calendars_to_process.append(config.calendar)
-
-        # Add calendars from the new field if available
-        if config.calendars:
-            calendars_to_process.extend(config.calendars)
-
-        for calendar_config in calendars_to_process:
+        for calendar_config in config.calendars:
             calendar_data = get_calendar(calendar_config)
             input_calendar = Calendar.from_ical(calendar_data)