diff --git a/client/modules/crm/src/views/meeting/fields/date-end.js b/client/modules/crm/src/views/meeting/fields/date-end.js
index 6a9e1dd327..dae266b8ca 100644
--- a/client/modules/crm/src/views/meeting/fields/date-end.js
+++ b/client/modules/crm/src/views/meeting/fields/date-end.js
@@ -36,6 +36,8 @@ define('crm:views/meeting/fields/date-end', 'views/fields/datetime-optional', fu
 
         noneOptionIsHidden: true,
 
+        isEnd: true,
+
         setup: function () {
             Dep.prototype.setup.call(this);
 
diff --git a/client/modules/crm/src/views/task/fields/date-end.js b/client/modules/crm/src/views/task/fields/date-end.js
index 0ed5213fab..e55440fb28 100644
--- a/client/modules/crm/src/views/task/fields/date-end.js
+++ b/client/modules/crm/src/views/task/fields/date-end.js
@@ -34,6 +34,8 @@ Espo.define('crm:views/task/fields/date-end', 'views/fields/datetime-optional',
 
         listTemplate: 'crm:task/fields/date-end/detail',
 
+        isEnd: true,
+
         data: function () {
             var data = Dep.prototype.data.call(this);
 
diff --git a/client/src/views/fields/datetime-optional.js b/client/src/views/fields/datetime-optional.js
index 4052fd14ed..0c64242822 100644
--- a/client/src/views/fields/datetime-optional.js
+++ b/client/src/views/fields/datetime-optional.js
@@ -84,7 +84,7 @@ define('views/fields/datetime-optional', 'views/fields/datetime', function (Dep)
                 noneOption: [{
                     label: this.noneOption,
                     value: this.noneOption,
-                }]
+                }],
             };
 
             if (this.emptyTimeInInlineEditDisabled && this.isInlineEditMode() || this.noneOptionIsHidden) {
@@ -93,7 +93,7 @@ define('views/fields/datetime-optional', 'views/fields/datetime', function (Dep)
 
             $time.timepicker(o);
 
-            $time.parent().find('button.time-picker-btn').on('click', function () {
+            $time.parent().find('button.time-picker-btn').on('click', () => {
                 $time.timepicker('show');
             });
         },
@@ -113,14 +113,17 @@ define('views/fields/datetime-optional', 'views/fields/datetime', function (Dep)
 
                 data[this.name] = value;
                 data[this.nameDate] = null;
-            } else {
+            }
+            else {
                 if (date !== '') {
                     data[this.nameDate] = this.getDateTime().fromDisplayDate(date);
 
                     var dateTimeValue = data[this.nameDate] + ' 00:00:00';
 
-                    dateTimeValue = moment.utc(dateTimeValue)
-                        .tz(this.getConfig().get('timeZone') || 'UTC')
+                    dateTimeValue = moment
+                        .tz(dateTimeValue, this.getConfig().get('timeZone') || 'UTC')
+                        .add(this.isEnd ? 1 : 0, 'days')
+                        .utc()
                         .format(this.getDateTime().internalDateTimeFullFormat);
 
                     data[this.name] = dateTimeValue;
@@ -130,6 +133,7 @@ define('views/fields/datetime-optional', 'views/fields/datetime', function (Dep)
                     data[this.name] = null;
                 }
             }
+
             return data;
         },
 
@@ -190,7 +194,8 @@ define('views/fields/datetime-optional', 'views/fields/datetime', function (Dep)
         validateRequired: function () {
             if (this.isRequired()) {
                 if (this.model.get(this.name) === null && this.model.get(this.nameDate) === null) {
-                    var msg = this.translate('fieldIsRequired', 'messages').replace('{field}', this.getLabelText());
+                    var msg = this.translate('fieldIsRequired', 'messages')
+                        .replace('{field}', this.getLabelText());
 
                     this.showValidationMessage(msg);
 
diff --git a/client/src/views/fields/duration.js b/client/src/views/fields/duration.js
index 850d63c73b..c4913ea19a 100644
--- a/client/src/views/fields/duration.js
+++ b/client/src/views/fields/duration.js
@@ -69,20 +69,21 @@ define('views/fields/duration', 'views/fields/enum', function (Dep) {
                 this.seconds = moment(
                     this.model.get(this.endField)).unix() - moment(this.model.get(this.startField)
                 ).unix();
-            }
-            else {
-                if (start) {
-                    var end = this._getDateEnd();
 
-                    this.model.set(this.endField, end, {silent: true});
-                }
+                return;
+            }
+
+            if (start) {
+                var end = this._getDateEnd();
+
+                this.model.set(this.endField, end, {silent: true});
             }
         },
 
         init: function () {
             Dep.prototype.init.call(this);
 
-            this.listenTo(this, 'render', function () {
+            this.listenTo(this, 'render', () => {
                 this.calculateSeconds();
 
                 var durationOptions = '';
@@ -93,19 +94,20 @@ define('views/fields/duration', 'views/fields/enum', function (Dep) {
                     options.push(this.seconds);
                 }
 
-                options.sort(function (a, b) {
+                options.sort((a, b) => {
                     return a - b;
                 });
 
-                options.forEach(function (d) {
+                options.forEach((d) => {
                     durationOptions += '<option value="' + d + '" ' +
-                        (d === this.seconds ? 'selected' : '') + '>' + this.stringifyDuration(d) + '</option>';
-                }.bind(this));
+                        (d === this.seconds ? 'selected' : '') + '>' +
+                        this.stringifyDuration(d) + '</option>';
+                });
 
                 this.durationOptions = durationOptions;
 
                 this.stringValue = this.stringifyDuration(this.seconds);
-            }.bind(this));
+            });
         },
 
         setup: function () {
@@ -172,19 +174,19 @@ define('views/fields/duration', 'views/fields/enum', function (Dep) {
             if (this.mode === 'edit') {
                 this.$duration = this.$el.find('.main-element');
 
-                this.$duration.on('change', function () {
+                this.$duration.on('change', () => {
                     this.seconds = parseInt(this.$duration.val());
 
                     this.updateDateEnd();
 
                     this.$duration.find('option.custom').remove();
-                }.bind(this));
+                });
             }
 
             this.stopListening(this.model, 'change:' + this.endField);
             this.stopListening(this.model, 'change:' + this.endField);
 
-            this.listenTo(this.model, 'change:' + this.endField, function () {
+            this.listenTo(this.model, 'change:' + this.endField, () => {
                 var start = this.model.get(this.startField);
                 var end = this.model.get(this.endField);
 
@@ -195,7 +197,7 @@ define('views/fields/duration', 'views/fields/enum', function (Dep) {
                 this.seconds = moment(end).unix() - moment(start).unix();
 
                 this.updateDuration();
-            }.bind(this));
+            });
 
             this.listenTo(this.model, 'change:' + this.startField, this.updateDateEnd);
 
@@ -211,9 +213,9 @@ define('views/fields/duration', 'views/fields/enum', function (Dep) {
                             this.updateDateEnd();
                         }
                         else {
-                            this.endFieldView.once('after:render', function () {
+                            this.endFieldView.once('after:render', () => {
                                 this.updateDateEnd();
-                            }.bind(this));
+                            });
                         }
                     }
                 }
@@ -235,7 +237,10 @@ define('views/fields/duration', 'views/fields/enum', function (Dep) {
             if (seconds) {
                 endUnix = moment.utc(start).unix() + seconds;
 
-                end = moment.unix(endUnix).utc().format(this.getDateTime().internalDateFormat);
+                end = moment.unix(endUnix)
+                    .utc()
+                    .add(-1, 'day')
+                    .format(this.getDateTime().internalDateFormat);
             }
             else {
                 end = start;
@@ -272,20 +277,19 @@ define('views/fields/duration', 'views/fields/enum', function (Dep) {
             if (this.model.get('isAllDay')) {
                 var end = this._getDateEndDate();
 
-                setTimeout(function () {
+                setTimeout(() => {
                     this.model.set(this.endField + 'Date', end, {updatedByDuration: true});
-                }.bind(this), 1);
+                }, 1);
 
                 return;
             }
 
             var end = this._getDateEnd();
 
-            setTimeout(function () {
+            setTimeout(() => {
                 this.model.set(this.endField, end, {updatedByDuration: true});
-
                 this.model.set(this.endField + 'Date', null);
-            }.bind(this), 1);
+            }, 1);
         },
 
         updateDuration: function () {
@@ -294,42 +298,46 @@ define('views/fields/duration', 'views/fields/enum', function (Dep) {
             if (seconds < 0) {
                 if (this.mode === 'edit') {
                     this.$duration.val('');
+
+                    return;
                 }
-                else {
-                    this.setup();
-                    this.render();
-                }
+
+                this.setup();
+                this.render();
+
+                return;
             }
-            else {
-                if (this.mode === 'edit') {
-                    this.$duration.find('option.custom').remove();
 
-                    var $o = $('<option>')
-                        .val(seconds)
-                        .text(this.stringifyDuration(seconds))
-                        .addClass('custom');
+            if (this.mode === 'edit') {
+                this.$duration.find('option.custom').remove();
 
-                    var $found = this.$duration.find('option').filter(function (i, el) {
+                var $o = $('<option>')
+                    .val(seconds)
+                    .text(this.stringifyDuration(seconds))
+                    .addClass('custom');
+
+                var $found = this.$duration.find('option')
+                    .filter((i, el) => {
                         return $(el).val() >= seconds;
-                    }).first();
+                    })
+                    .first();
 
-                    if ($found.length) {
-                        if (parseInt($found.val()) !== seconds) {
-                            $o.insertBefore($found);
-                        };
-                    }
-                    else {
-                        $o.appendTo(this.$duration);
-                    }
-
-                    this.$duration.val(seconds);
+                if ($found.length) {
+                    if (parseInt($found.val()) !== seconds) {
+                        $o.insertBefore($found);
+                    };
                 }
                 else {
-                    this.setup();
-
-                    this.render();
+                    $o.appendTo(this.$duration);
                 }
+
+                this.$duration.val(seconds);
+
+                return;
             }
+
+            this.setup();
+            this.render();
         },
 
         fetch: function () {