diff --git a/api/js/etemplate/Et2Date/Et2Date.ts b/api/js/etemplate/Et2Date/Et2Date.ts
index 88f94ead87..726360533d 100644
--- a/api/js/etemplate/Et2Date/Et2Date.ts
+++ b/api/js/etemplate/Et2Date/Et2Date.ts
@@ -442,8 +442,18 @@ export class Et2Date extends Et2InputWidget(FormControlMixin(ValidateMixin(LitFl
 			this.clear();
 			return;
 		}
+		let date;
+		// handle relative time (eg. "+3600" or "-3600") used in calendar
+		if (typeof value === 'string' && (value[0] === '+' || value[0] === '-'))
+		{
+			date = new Date(this.getValue());
+			date.set_value(date.getSeconds() + parseInt(value));
+		}
+		else
+		{
+			date = new Date(value);
+		}
 		// Handle timezone offset, flatpickr uses local time
-		let date = new Date(value);
 		let formatDate = new Date(date.valueOf() + date.getTimezoneOffset() * 60 * 1000);
 		if(!this._instance)
 		{
diff --git a/calendar/js/app.ts b/calendar/js/app.ts
index 7d17438d91..c6dc25f258 100644
--- a/calendar/js/app.ts
+++ b/calendar/js/app.ts
@@ -3235,7 +3235,7 @@ export class CalendarApp extends EgwApp
 				}
 			}
 
-			// If current state matches a favorite, hightlight it
+			// If current state matches a favorite, highlight it
 			this.highlight_favorite();
 
 			// Update app header
@@ -3980,7 +3980,7 @@ export class CalendarApp extends EgwApp
 						{
 							if (!month_before_day)
 							{
-								range += flatpickr.formatDate(first_format, "F");
+								range += egw.lang(flatpickr.formatDate(first_format, "F"));
 							}
 							if (first.getFullYear() != last.getFullYear() && datefmt[0] != 'Y')
 							{
@@ -4003,7 +4003,7 @@ export class CalendarApp extends EgwApp
 
 							if (month_before_day)
 							{
-								range += flatpickr.formatDate(last_format, 'l');
+								range += egw.lang(flatpickr.formatDate(last_format, 'l'));
 							}
 						}
 						else if (last)
@@ -4024,7 +4024,7 @@ export class CalendarApp extends EgwApp
 						break;
 					case 'm':
 					case 'M':
-						range += ' ' + flatpickr.formatDate(month_before_day || !last ? first_format : last_format, "l") + ' ';
+						range += ' ' + egw.lang(flatpickr.formatDate(month_before_day || !last ? first_format : last_format, "F")) + ' ';
 						break;
 					case 'Y':
 						if (datefmt[0] != 'm')
diff --git a/calendar/js/et2_widget_daycol.ts b/calendar/js/et2_widget_daycol.ts
index b1ec88559c..75496a156a 100644
--- a/calendar/js/et2_widget_daycol.ts
+++ b/calendar/js/et2_widget_daycol.ts
@@ -258,8 +258,8 @@ export class et2_calendar_daycol extends et2_valueWidget implements et2_IDetache
 			// Add timezone offset back in, or formatDate will lose those hours
 			const formatDate = new Date(this.date.valueOf() + this.date.getTimezoneOffset() * 60 * 1000);
 
-			this.title.html('<span class="long_date">' + flatpickr.formatDate(formatDate, 'l') +
-				'</span><span class="short_date">' + flatpickr.formatDate(formatDate, 'D') + '</span>' +
+			this.title.html('<span class="long_date">' + egw.lang(flatpickr.formatDate(formatDate, 'l')) +
+				'</span><span class="short_date">' + egw.lang(flatpickr.formatDate(formatDate, 'D')) + '</span>' +
 				flatpickr.formatDate(formatDate, 'd'));
 		}
 		this.title