diff --git a/src/app.tsx b/src/app.tsx
index 6087672..82cb40d 100644
--- a/src/app.tsx
+++ b/src/app.tsx
@@ -2,16 +2,13 @@ import React from 'react';
 import { Helmet } from 'react-helmet';
 import { Global } from '@emotion/react'
 import { BrowserRouter } from 'react-router-dom';
-import ruLocale from 'dayjs/locale/ru';
-import dayjs from 'dayjs';
+import dayjs from './utils/dayjs-config';
 import { useTranslation } from 'react-i18next';
 import { ChakraProvider, ColorModeScript, extendTheme } from '@chakra-ui/react'
 
 import { Dashboard } from './dashboard';
 import { globalStyles } from './global.styles';
 
-dayjs.locale('ru', ruLocale);
-
 // Расширяем тему Chakra UI
 const theme = extendTheme({
   config: {
diff --git a/src/pages/attendance/components/AddDataDialog.tsx b/src/pages/attendance/components/AddDataDialog.tsx
index 6bc23b0..1a4152a 100644
--- a/src/pages/attendance/components/AddDataDialog.tsx
+++ b/src/pages/attendance/components/AddDataDialog.tsx
@@ -21,7 +21,8 @@ import {
   useColorMode,
 } from "@chakra-ui/react";
 import { useTranslation } from 'react-i18next';
-import dayjs from 'dayjs';
+import dayjs from "../../../utils/dayjs-config";
+import { formatDate } from "../../../utils/dayjs-config";
 import UserSelect from "../../../components/user-select";
 
 interface AttendanceEntry {
@@ -41,7 +42,7 @@ const AddDataDialog = ({ isOpen, onClose, onAddData }: AddDataDialogProps) => {
   const { colorMode } = useColorMode();
   const { t } = useTranslation();
   const [name, setName] = useState("");
-  const [date, setDate] = useState(dayjs().format('YYYY-MM-DD'));
+  const [date, setDate] = useState(formatDate(dayjs().toDate(), 'YYYY-MM-DD'));
   const [selectedStudents, setSelectedStudents] = useState<any[]>([]);
   const [selectedTeachers, setSelectedTeachers] = useState<any[]>([]);
 
@@ -60,7 +61,7 @@ const AddDataDialog = ({ isOpen, onClose, onAddData }: AddDataDialogProps) => {
 
   const resetForm = () => {
     setName("");
-    setDate(dayjs().format('YYYY-MM-DD'));
+    setDate(formatDate(dayjs().toDate(), 'YYYY-MM-DD'));
     setSelectedStudents([]);
     setSelectedTeachers([]);
   };
diff --git a/src/pages/attendance/components/AttendanceTable.tsx b/src/pages/attendance/components/AttendanceTable.tsx
index a3206d0..eb690ec 100644
--- a/src/pages/attendance/components/AttendanceTable.tsx
+++ b/src/pages/attendance/components/AttendanceTable.tsx
@@ -33,6 +33,7 @@ import { useTranslation } from 'react-i18next'
 import { getGravatarURL } from '../../../utils/gravatar'
 import { ShortText } from './ShortText'
 import { AttendanceData } from '../hooks'
+import { formatDate } from '../../../utils/dayjs-config'
 
 interface AttendanceTableProps {
   data: AttendanceData
@@ -120,7 +121,7 @@ export const AttendanceTable: React.FC<AttendanceTableProps> = ({ data }) => {
       })
       
       // Добавляем дату
-      row.push(dayjs(lesson.date).format('DD.MM.YYYY'))
+      row.push(formatDate(lesson.date, 'DD.MM.YYYY'))
       
       // Добавляем полное название занятия (без сокращений)
       row.push(lesson.name)
@@ -230,7 +231,7 @@ export const AttendanceTable: React.FC<AttendanceTableProps> = ({ data }) => {
                 </Td>
               )
             })}
-            <Td>{dayjs(lesson.date).format('DD.MM.YYYY')}</Td>
+            <Td>{formatDate(lesson.date, 'DD.MM.YYYY')}</Td>
             <Td><ShortText text={lesson.name} /></Td>
 
             {data.students.map((st) => {
diff --git a/src/pages/course-list/course-card.tsx b/src/pages/course-list/course-card.tsx
index dc5f952..14a9519 100644
--- a/src/pages/course-list/course-card.tsx
+++ b/src/pages/course-list/course-card.tsx
@@ -1,4 +1,5 @@
 import React, { useCallback, useEffect, useState, useMemo } from 'react'
+import { formatDate } from '../../utils/dayjs-config'
 import dayjs from 'dayjs'
 import { Link as ConnectedLink, generatePath } from 'react-router-dom'
 import { getNavigationValue } from '@brojs/cli'
@@ -231,7 +232,7 @@ export const CourseCard = ({ course }: { course: Course }) => {
               <Badge colorScheme="blue">
                 <HStack spacing={1}>
                   <CalendarIcon boxSize="3" />
-                  <Text>{dayjs(course.startDt).format('DD.MM.YYYY')}</Text>
+                  <Text>{formatDate(course.startDt, 'DD.MM.YYYY')}</Text>
                 </HStack>
               </Badge>
               <Badge colorScheme="purple">
@@ -243,7 +244,7 @@ export const CourseCard = ({ course }: { course: Course }) => {
               <Badge colorScheme="blue">
                 <HStack spacing={1}>
                   <CalendarIcon boxSize="3" />
-                  <Text>{dayjs(course.startDt).format('DD.MM.YYYY')}</Text>
+                  <Text>{formatDate(course.startDt, 'DD.MM.YYYY')}</Text>
                 </HStack>
               </Badge>
               <Badge colorScheme="purple">
@@ -311,10 +312,12 @@ export const CourseCard = ({ course }: { course: Course }) => {
                   {populatedCourse.data?.lessons
                     .filter(lesson => dayjs(lesson.date).isAfter(dayjs()))
                     .sort((a, b) => dayjs(a.date).valueOf() - dayjs(b.date).valueOf())[0]?.date
-                    ? dayjs(populatedCourse.data?.lessons
-                      .filter(lesson => dayjs(lesson.date).isAfter(dayjs()))
-                      .sort((a, b) => dayjs(a.date).valueOf() - dayjs(b.date).valueOf())[0]?.date)
-                      .format('DD.MM.YYYY')
+                    ? formatDate(
+                        populatedCourse.data?.lessons
+                          .filter(lesson => dayjs(lesson.date).isAfter(dayjs()))
+                          .sort((a, b) => dayjs(a.date).valueOf() - dayjs(b.date).valueOf())[0]?.date,
+                        'DD.MM.YYYY'
+                      )
                     : t('journal.pl.common.noData')
                   }
                 </Text>
@@ -455,7 +458,7 @@ export const CourseCard = ({ course }: { course: Course }) => {
                             <HStack spacing={2} mt={1} flexWrap="wrap">
                               <Tag size="sm" colorScheme={isPast ? "green" : "blue"} borderRadius="full">
                                 <TagLeftIcon as={CalendarIcon} boxSize='10px' />
-                                <TagLabel>{dayjs(lesson.date).format('DD.MM.YYYY')}</TagLabel>
+                                <TagLabel>{formatDate(lesson.date, 'DD.MM.YYYY')}</TagLabel>
                               </Tag>
                               {isPast && lessonAttendance && (
                                 <Tag 
diff --git a/src/pages/course-list/hooks/useCreateCourse.ts b/src/pages/course-list/hooks/useCreateCourse.ts
index 7ffc7cf..bd8ac9b 100644
--- a/src/pages/course-list/hooks/useCreateCourse.ts
+++ b/src/pages/course-list/hooks/useCreateCourse.ts
@@ -1,8 +1,9 @@
 import { useRef, useEffect } from 'react'
-import dayjs from 'dayjs'
+import dayjs from '../../../utils/dayjs-config'
 import { useForm } from 'react-hook-form'
 import { useToast } from '@chakra-ui/react'
 import { useTranslation } from 'react-i18next'
+import { formatDate } from '../../../utils/dayjs-config'
 
 import { api } from '../../../__data__/api/api'
 
@@ -30,7 +31,7 @@ export const useCreateCourse = (onSuccess: () => void) => {
     getValues,
   } = useForm<NewCourseForm>({
     defaultValues: {
-      startDt: dayjs().format('YYYY-MM-DD'),
+      startDt: formatDate(dayjs().toDate(), 'YYYY-MM-DD'),
       name: t('journal.pl.course.defaultName'),
     },
   })
diff --git a/src/pages/course-list/hooks/useGroupedCourses.ts b/src/pages/course-list/hooks/useGroupedCourses.ts
index c5098ab..6329b72 100644
--- a/src/pages/course-list/hooks/useGroupedCourses.ts
+++ b/src/pages/course-list/hooks/useGroupedCourses.ts
@@ -1,5 +1,5 @@
 import { useMemo } from 'react'
-import dayjs from 'dayjs'
+import dayjs, { formatDate } from '../../../utils/dayjs-config'
 import { Course } from '../../../__data__/model'
 
 /**
@@ -20,7 +20,7 @@ export const useGroupedCourses = (courses?: Course[]) => {
     
     // Группируем по годам
     sortedCourses.forEach(course => {
-      const year = dayjs(course.startDt).format('YYYY')
+      const year = formatDate(course.startDt, 'YYYY')
       if (!grouped[year]) {
         grouped[year] = []
       }
diff --git a/src/pages/lesson-details.tsx b/src/pages/lesson-details.tsx
index 5699f00..25196c2 100644
--- a/src/pages/lesson-details.tsx
+++ b/src/pages/lesson-details.tsx
@@ -1,6 +1,5 @@
 import React, { useEffect, useRef, useMemo } from 'react'
 import { useParams, Link } from 'react-router-dom'
-import dayjs from 'dayjs'
 import QRCode from 'qrcode'
 import { sha256 } from 'js-sha256'
 import { getConfigValue, getNavigationValue } from '@brojs/cli'
@@ -21,6 +20,7 @@ import { useTranslation } from 'react-i18next'
 import { api } from '../__data__/api/api'
 import { User } from '../__data__/model'
 import { UserCard } from '../components/user-card'
+import { formatDate } from '../utils/dayjs-config'
 
 import {
   QRCanvas,
@@ -209,8 +209,8 @@ const LessonDetail = () => {
             borderRadius="xl" 
             bg={colorMode === "light" ? "gray.50" : "gray.700"}
             boxShadow="md"
-          ><Box as="span">
-          {dayjs(accessCode?.body?.lesson?.date).format(t('journal.pl.lesson.dateFormat'))}{' '}
+          ><Box pb={3}>
+          {formatDate(accessCode?.body?.lesson?.date, t('journal.pl.lesson.dateFormat'))}{' '}
           {t('journal.pl.common.marked')} - {accessCode?.body?.lesson?.students?.length}{' '}
           {AllStudents.isSuccess
             ? `/ ${AllStudents?.data?.body?.length}`
diff --git a/src/pages/lesson-list/components/item.tsx b/src/pages/lesson-list/components/item.tsx
index 58fa5ee..df92be0 100644
--- a/src/pages/lesson-list/components/item.tsx
+++ b/src/pages/lesson-list/components/item.tsx
@@ -1,5 +1,5 @@
 import React, { useEffect, useRef, useState } from 'react'
-import dayjs from 'dayjs'
+import { formatDate } from '../../../utils/dayjs-config'
 import { Link } from 'react-router-dom'
 import { getNavigationValue, getFeatures } from '@brojs/cli'
 import {
@@ -133,7 +133,7 @@ export const Item: React.FC<ItemProps> = ({
       <>
         <Flex justify="space-between" align="center" mb={2}>
           <Text fontWeight="medium">{name}</Text>
-          <Text fontSize="sm">{dayjs(date).format(groupByDate ? 'HH:mm' : 'HH:mm DD.MM.YY')}</Text>
+          <Text fontSize="sm">{formatDate(date, groupByDate ? 'HH:mm' : 'HH:mm DD.MM.YY')}</Text>
         </Flex>
         
         <Flex justify="space-between" align="center">
@@ -193,7 +193,7 @@ export const Item: React.FC<ItemProps> = ({
         </Td>
       )}
       <Td textAlign="center">
-        {dayjs(date).format(groupByDate ? 'HH:mm' : 'HH:mm DD.MM.YY')}
+        {formatDate(date, groupByDate ? 'HH:mm' : 'HH:mm DD.MM.YY')}
       </Td>
       <Td>{name}</Td>
       {isTeacher && (
diff --git a/src/pages/lesson-list/components/lesson-items.tsx b/src/pages/lesson-list/components/lesson-items.tsx
index 109918f..ee9bca0 100644
--- a/src/pages/lesson-list/components/lesson-items.tsx
+++ b/src/pages/lesson-list/components/lesson-items.tsx
@@ -1,5 +1,5 @@
 import React from 'react'
-import dayjs from 'dayjs'
+import { formatDate } from '../../../utils/dayjs-config'
 import {
   Tr,
   Td,
@@ -45,7 +45,7 @@ export const LessonItems: React.FC<LessonItemProps> = ({
             borderRadius="md"
             _dark={{ bg: "gray.700" }}
           >
-            <Text fontWeight="bold">{dayjs(date).format('DD MMMM YYYY')}</Text>
+            <Text fontWeight="bold">{formatDate(date, 'DD MMMM YYYY')}</Text>
           </Box>
         )}
         {lessons.map((lesson) => (
@@ -78,7 +78,7 @@ export const LessonItems: React.FC<LessonItemProps> = ({
       {date && (
         <Tr>
           <Td colSpan={isTeacher ? 5 : 3}>
-            {dayjs(date).format('DD MMMM YYYY')}
+            {formatDate(date, 'DD MMMM YYYY')}
           </Td>
         </Tr>
       )}
diff --git a/src/pages/lesson-list/components/lessons-form.tsx b/src/pages/lesson-list/components/lessons-form.tsx
index c5a877c..acdf034 100644
--- a/src/pages/lesson-list/components/lessons-form.tsx
+++ b/src/pages/lesson-list/components/lessons-form.tsx
@@ -30,6 +30,7 @@ import { AddIcon, CheckIcon, WarningIcon, RepeatIcon } from '@chakra-ui/icons'
 import { useTranslation } from 'react-i18next'
 import { FaRobot } from 'react-icons/fa'
 import dayjs from 'dayjs'
+import { formatDate } from '../../../utils/dayjs-config'
 
 import { dateToCalendarFormat } from '../../../utils/time'
 import { Lesson } from '../../../__data__/model'
@@ -294,7 +295,7 @@ export const LessonForm = ({
                           {isSelected && <CheckIcon color="green.400" />}
                         </Flex>
                         <Text fontSize="sm" color={textSecondaryColor}>
-                          {dayjs(suggestion.date).format('DD.MM.YYYY HH:mm')}
+                          {formatDate(suggestion.date, 'DD.MM.YYYY HH:mm')}
                         </Text>
                       </Box>
                     );
diff --git a/src/pages/lesson-list/components/statistics.tsx b/src/pages/lesson-list/components/statistics.tsx
index 8b11bf1..d606f09 100644
--- a/src/pages/lesson-list/components/statistics.tsx
+++ b/src/pages/lesson-list/components/statistics.tsx
@@ -1,5 +1,6 @@
 import React, { useMemo } from 'react'
 import dayjs from 'dayjs'
+import { formatDate } from '../../../utils/dayjs-config'
 import {
   Box,
   Heading,
@@ -45,7 +46,7 @@ export const CourseStatistics: React.FC<CourseStatisticsProps> = ({ lessons = []
   
   // Вычисляем статистику курса
   const stats = useMemo(() => {
-    if (!lessons.length) {
+    if (!lessons || lessons.length === 0) {
       return {
         totalLessons: 0,
         completedLessons: 0,
@@ -215,10 +216,10 @@ export const CourseStatistics: React.FC<CourseStatisticsProps> = ({ lessons = []
             {stats.attendanceTrend !== 0 && (
               <Flex align="center">
                 <StatArrow 
-                  type={stats.attendanceTrend > 0 ? 'increase' : 'decrease'} 
+                  type={Number(stats.attendanceTrend) > 0 ? 'increase' : 'decrease'} 
                 />
                 <Text>
-                  {Math.abs(Math.round(stats.attendanceTrend))}%
+                  {Math.abs(Math.round(Number(stats.attendanceTrend)))}%
                 </Text>
               </Flex>
             )}
@@ -261,7 +262,7 @@ export const CourseStatistics: React.FC<CourseStatisticsProps> = ({ lessons = []
           </Flex>
           <StatNumber fontSize="xl">
             {stats.nextLessonDate 
-              ? dayjs(stats.nextLessonDate).format('DD.MM.YYYY')
+              ? formatDate(stats.nextLessonDate, 'DD.MM.YYYY')
               : t('journal.pl.statistics.noUpcoming')
             }
           </StatNumber>
diff --git a/src/pages/lesson-list/lesson-list.tsx b/src/pages/lesson-list/lesson-list.tsx
index 8a00576..6b69c85 100644
--- a/src/pages/lesson-list/lesson-list.tsx
+++ b/src/pages/lesson-list/lesson-list.tsx
@@ -1,5 +1,5 @@
 import React, { useEffect, useMemo, useRef, useState } from 'react'
-import dayjs from 'dayjs'
+import dayjs, { formatDate } from '../../utils/dayjs-config'
 import { generatePath, Link, useParams } from 'react-router-dom'
 import { getNavigationValue, getFeatures } from '@brojs/cli'
 import {
@@ -277,7 +277,7 @@ const LessonList = () => {
         <AlertDialogOverlay>
           <AlertDialogContent>
             <AlertDialogHeader fontSize="lg" fontWeight="bold">
-              {t('journal.pl.lesson.deleteConfirm', { date: dayjs(lessonToDelete?.date).format('DD.MM.YY') })}
+              {t('journal.pl.lesson.deleteConfirm', { date: formatDate(lessonToDelete?.date, 'DD.MM.YY') })}
             </AlertDialogHeader>
 
             <AlertDialogBody>
diff --git a/src/pages/user-page.tsx b/src/pages/user-page.tsx
index ebddd0e..ccdfbf6 100644
--- a/src/pages/user-page.tsx
+++ b/src/pages/user-page.tsx
@@ -4,7 +4,7 @@ import { useTranslation } from 'react-i18next'
 import { motion, AnimatePresence } from 'framer-motion'
 
 import { api } from '../__data__/api/api'
-import dayjs from 'dayjs'
+import { formatDate } from '../utils/dayjs-config'
 import {
   Alert,
   AlertIcon,
@@ -145,7 +145,7 @@ const UserPage = () => {
 
           <Flex align="center" justify="space-between" mt={3}>
             <Text color={colorMode === "light" ? "gray.600" : "gray.300"}>
-              {dayjs(ls.data?.body?.date).format(t('journal.pl.lesson.dateFormat'))}
+              {formatDate(ls.data?.body?.date, t('journal.pl.lesson.dateFormat'))}
             </Text>
             
             <Badge colorScheme="green" fontSize="md" borderRadius="full" px={3} py={1}>
diff --git a/src/utils/dayjs-config.ts b/src/utils/dayjs-config.ts
new file mode 100644
index 0000000..7392238
--- /dev/null
+++ b/src/utils/dayjs-config.ts
@@ -0,0 +1,30 @@
+import dayjs from 'dayjs';
+import 'dayjs/locale/ru';
+import 'dayjs/locale/en';
+import i18next from 'i18next';
+
+// Функция для обновления локали dayjs при изменении языка в i18next
+export const updateDayjsLocale = () => {
+  const currentLocale = i18next.language;
+  
+  // Убедимся, что локаль поддерживается, иначе используем 'en'
+  const locale = ['ru', 'en'].includes(currentLocale) ? currentLocale : 'en';
+  
+  // Установим локаль для dayjs
+  dayjs.locale(locale);
+};
+
+// Слушаем изменения языка и обновляем локаль dayjs
+i18next.on('languageChanged', () => {
+  updateDayjsLocale();
+});
+
+// Вызываем функцию инициализации при импорте
+updateDayjsLocale();
+
+// Хелпер для форматирования даты с учетом текущей локали
+export const formatDate = (date: string | Date | number, format = 'DD.MM.YYYY') => {
+  return dayjs(date).format(format);
+};
+
+export default dayjs; 
\ No newline at end of file
diff --git a/src/utils/time.ts b/src/utils/time.ts
index 5806637..21c84c8 100644
--- a/src/utils/time.ts
+++ b/src/utils/time.ts
@@ -1,3 +1,3 @@
-import dayjs from "dayjs";
+import dayjs, { formatDate } from "./dayjs-config";
 
-export const dateToCalendarFormat = (date?: string) => dayjs(date).format('YYYY-MM-DDTHH:mm')
+export const dateToCalendarFormat = (date?: string) => formatDate(date, 'YYYY-MM-DDTHH:mm')