diff --git a/.idea/codeStyles/Project.xml b/.idea/codeStyles/Project.xml
index 0ac66f64..ab784474 100644
--- a/.idea/codeStyles/Project.xml
+++ b/.idea/codeStyles/Project.xml
@@ -7,15 +7,6 @@
           <package name="kotlinx.android.synthetic" alias="false" withSubpackages="true" />
         </value>
       </option>
-      <option name="PACKAGES_IMPORT_LAYOUT">
-        <value>
-          <package name="" alias="false" withSubpackages="true" />
-          <package name="java" alias="false" withSubpackages="true" />
-          <package name="javax" alias="false" withSubpackages="true" />
-          <package name="kotlin" alias="false" withSubpackages="true" />
-          <package name="" alias="true" withSubpackages="true" />
-        </value>
-      </option>
       <option name="NAME_COUNT_TO_USE_STAR_IMPORT" value="2147483647" />
       <option name="NAME_COUNT_TO_USE_STAR_IMPORT_FOR_MEMBERS" value="2147483647" />
       <option name="WRAP_ELVIS_EXPRESSIONS" value="0" />
diff --git a/app/build.gradle b/app/build.gradle
index 74d3e37d..81b6bd73 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -117,7 +117,6 @@ android {
     }
 
     kotlinOptions {
-        useIR = true
         jvmTarget = "1.8"
         freeCompilerArgs += ["-Xopt-in=kotlin.RequiresOptIn", "-Xjvm-default=all"]
     }
@@ -165,7 +164,7 @@ dependencies {
     coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:1.1.5'
 
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.4.3'
+    implementation "org.jetbrains.kotlinx:kotlinx-coroutines-android:1.5.0-RC"
 
     implementation "androidx.core:core-ktx:1.3.2"
     implementation "androidx.activity:activity-ktx:1.2.3"
@@ -197,7 +196,6 @@ dependencies {
     implementation "com.google.dagger:hilt-android:$hilt_version"
     kapt "com.google.dagger:hilt-android-compiler:$hilt_version"
     implementation "androidx.hilt:hilt-work:$work_hilt"
-    kapt "androidx.hilt:hilt-compiler:$work_hilt"
 
     implementation "com.ncapdevi:frag-nav:3.3.0"
     implementation "com.github.YarikSOffice:lingver:1.3.0"
diff --git a/app/jacoco.gradle b/app/jacoco.gradle
index 1fb1ebd7..9c1f5b1c 100644
--- a/app/jacoco.gradle
+++ b/app/jacoco.gradle
@@ -1,7 +1,7 @@
 apply plugin: "jacoco"
 
 jacoco {
-    toolVersion "0.8.6"
+    toolVersion "0.8.7"
     reportsDirectory = file("$buildDir/reports")
 }
 
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/attendance/AttendancePresenter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/attendance/AttendancePresenter.kt
index b03db91a..333e7103 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/attendance/AttendancePresenter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/attendance/AttendancePresenter.kt
@@ -11,6 +11,7 @@ import io.github.wulkanowy.ui.base.BasePresenter
 import io.github.wulkanowy.ui.base.ErrorHandler
 import io.github.wulkanowy.utils.AnalyticsHelper
 import io.github.wulkanowy.utils.afterLoading
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.flowWithResource
 import io.github.wulkanowy.utils.flowWithResourceIn
 import io.github.wulkanowy.utils.getLastSchoolDayIfHoliday
@@ -319,7 +320,7 @@ class AttendancePresenter @Inject constructor(
         view?.apply {
             showPreButton(!currentDate.minusDays(1).isHolidays)
             showNextButton(!currentDate.plusDays(1).isHolidays)
-            updateNavigationDay(currentDate.toFormattedString("EEEE, dd.MM").capitalize())
+            updateNavigationDay(currentDate.toFormattedString("EEEE, dd.MM").capitalise())
         }
     }
 }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/attendance/summary/AttendanceSummaryAdapter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/attendance/summary/AttendanceSummaryAdapter.kt
index 4250a910..a2b6abfb 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/attendance/summary/AttendanceSummaryAdapter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/attendance/summary/AttendanceSummaryAdapter.kt
@@ -76,13 +76,13 @@ class AttendanceSummaryAdapter @Inject constructor() :
 
     private fun getTotalItem() = AttendanceSummary(
         month = Month.APRIL,
-        presence = items.sumBy { it.presence },
-        absence = items.sumBy { it.absence },
-        absenceExcused = items.sumBy { it.absenceExcused },
-        absenceForSchoolReasons = items.sumBy { it.absenceForSchoolReasons },
-        exemption = items.sumBy { it.exemption },
-        lateness = items.sumBy { it.lateness },
-        latenessExcused = items.sumBy { it.latenessExcused },
+        presence = items.sumOf { it.presence },
+        absence = items.sumOf { it.absence },
+        absenceExcused = items.sumOf { it.absenceExcused },
+        absenceForSchoolReasons = items.sumOf { it.absenceForSchoolReasons },
+        exemption = items.sumOf { it.exemption },
+        lateness = items.sumOf { it.lateness },
+        latenessExcused = items.sumOf { it.latenessExcused },
         diaryId = -1,
         studentId = -1,
         subjectId = -1
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/exam/ExamAdapter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/exam/ExamAdapter.kt
index 53558739..4dc8afd3 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/exam/ExamAdapter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/exam/ExamAdapter.kt
@@ -7,6 +7,7 @@ import androidx.recyclerview.widget.RecyclerView
 import io.github.wulkanowy.data.db.entities.Exam
 import io.github.wulkanowy.databinding.HeaderExamBinding
 import io.github.wulkanowy.databinding.ItemExamBinding
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.toFormattedString
 import io.github.wulkanowy.utils.weekDayName
 import java.time.LocalDate
@@ -42,7 +43,7 @@ class ExamAdapter @Inject constructor() : RecyclerView.Adapter<RecyclerView.View
     @SuppressLint("DefaultLocale")
     private fun bindHeaderViewHolder(binding: HeaderExamBinding, date: LocalDate) {
         with(binding) {
-            examHeaderDay.text = date.weekDayName.capitalize()
+            examHeaderDay.text = date.weekDayName.capitalise()
             examHeaderDate.text = date.toFormattedString()
         }
     }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsAdapter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsAdapter.kt
index 6f932169..01631140 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsAdapter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsAdapter.kt
@@ -108,7 +108,7 @@ class GradeDetailsAdapter @Inject constructor() : BaseExpandableAdapter<Recycler
 
     private fun bindHeaderViewHolder(holder: HeaderViewHolder, header: GradeDetailsHeader, position: Int) {
         val headerPosition = headers.indexOf(items[position])
-        val adapterPosition = holder.adapterPosition
+        val adapterPosition = holder.bindingAdapterPosition
 
         with(holder.binding) {
             gradeHeaderDivider.visibility = if (adapterPosition == 0) View.GONE else View.VISIBLE
@@ -161,7 +161,7 @@ class GradeDetailsAdapter @Inject constructor() : BaseExpandableAdapter<Recycler
             gradeItemNote.visibility = if (!grade.isRead) View.VISIBLE else View.GONE
 
             root.setOnClickListener {
-                holder.adapterPosition.let { if (it != NO_POSITION) onClickListener(grade, it) }
+                holder.bindingAdapterPosition.let { if (it != NO_POSITION) onClickListener(grade, it) }
             }
         }
     }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsPresenter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsPresenter.kt
index 6d86c7bb..7544d2aa 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsPresenter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/grade/details/GradeDetailsPresenter.kt
@@ -1,6 +1,5 @@
 package io.github.wulkanowy.ui.modules.grade.details
 
-import android.annotation.SuppressLint
 import io.github.wulkanowy.data.Status
 import io.github.wulkanowy.data.db.entities.Grade
 import io.github.wulkanowy.data.repositories.GradeRepository
@@ -202,8 +201,9 @@ class GradeDetailsPresenter @Inject constructor(
     }
 
     private fun updateNewGradesAmount(grades: List<GradeSubject>) {
-        newGradesAmount =
-            grades.sumBy { item -> item.grades.sumBy { grade -> if (!grade.isRead) 1 else 0 } }
+        newGradesAmount = grades.sumOf { item ->
+            item.grades.sumOf { grade -> (if (!grade.isRead) 1 else 0).toInt() }
+        }
     }
 
     private fun showErrorViewOnError(message: String, error: Throwable) {
@@ -217,7 +217,6 @@ class GradeDetailsPresenter @Inject constructor(
         }
     }
 
-    @SuppressLint("DefaultLocale")
     private fun createGradeItems(items: List<GradeSubject>): List<GradeDetailsItem> {
         return items
             .let { gradesWithAverages ->
@@ -228,7 +227,7 @@ class GradeDetailsPresenter @Inject constructor(
             .let {
                 when (preferencesRepository.gradeSortingMode) {
                     DATE -> it.sortedByDescending { gradeDetailsWithAverage -> gradeDetailsWithAverage.grades.firstOrNull()?.date }
-                    ALPHABETIC -> it.sortedBy { gradeDetailsWithAverage -> gradeDetailsWithAverage.subject.toLowerCase() }
+                    ALPHABETIC -> it.sortedBy { gradeDetailsWithAverage -> gradeDetailsWithAverage.subject.lowercase() }
                 }
             }
             .map { (subject, average, points, _, grades) ->
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/homework/HomeworkAdapter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/homework/HomeworkAdapter.kt
index 8ae06aeb..9dcd3d4a 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/homework/HomeworkAdapter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/homework/HomeworkAdapter.kt
@@ -8,6 +8,7 @@ import androidx.recyclerview.widget.RecyclerView
 import io.github.wulkanowy.data.db.entities.Homework
 import io.github.wulkanowy.databinding.HeaderHomeworkBinding
 import io.github.wulkanowy.databinding.ItemHomeworkBinding
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.toFormattedString
 import io.github.wulkanowy.utils.weekDayName
 import java.time.LocalDate
@@ -43,7 +44,7 @@ class HomeworkAdapter @Inject constructor() : RecyclerView.Adapter<RecyclerView.
     @SuppressLint("DefaultLocale")
     private fun bindHeaderViewHolder(binding: HeaderHomeworkBinding, date: LocalDate) {
         with(binding) {
-            homeworkHeaderDay.text = date.weekDayName.capitalize()
+            homeworkHeaderDay.text = date.weekDayName.capitalise()
             homeworkHeaderDate.text = date.toFormattedString()
         }
     }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/luckynumber/history/LuckyNumberHistoryAdapter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/luckynumber/history/LuckyNumberHistoryAdapter.kt
index 2a80de8c..0c1b89c8 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/luckynumber/history/LuckyNumberHistoryAdapter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/luckynumber/history/LuckyNumberHistoryAdapter.kt
@@ -6,6 +6,7 @@ import android.view.ViewGroup
 import androidx.recyclerview.widget.RecyclerView
 import io.github.wulkanowy.data.db.entities.LuckyNumber
 import io.github.wulkanowy.databinding.ItemLuckyNumberHistoryBinding
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.toFormattedString
 import io.github.wulkanowy.utils.weekDayName
 import javax.inject.Inject
@@ -25,7 +26,7 @@ class LuckyNumberHistoryAdapter @Inject constructor() :
     override fun onBindViewHolder(holder: ItemViewHolder, position: Int) {
         val item = items[position]
         with(holder.binding) {
-            luckyNumberHistoryWeekName.text = item.date.weekDayName.capitalize()
+            luckyNumberHistoryWeekName.text = item.date.weekDayName.capitalise()
             luckyNumberHistoryDate.text = item.date.toFormattedString()
             luckyNumberHistory.text = item.luckyNumber.toString()
         }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabAdapter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabAdapter.kt
index f0f65e08..bb12c8df 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabAdapter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabAdapter.kt
@@ -57,7 +57,7 @@ class MessageTabAdapter @Inject constructor() :
             messageItemAttachmentIcon.visibility = if (item.hasAttachments) View.VISIBLE else View.GONE
 
             root.setOnClickListener {
-                holder.adapterPosition.let { if (it != NO_POSITION) onClickListener(item, it) }
+                holder.bindingAdapterPosition.let { if (it != NO_POSITION) onClickListener(item, it) }
             }
         }
     }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabPresenter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabPresenter.kt
index c560a77d..0f4e8633 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabPresenter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/message/tab/MessageTabPresenter.kt
@@ -23,7 +23,6 @@ import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import me.xdrop.fuzzywuzzy.FuzzySearch
 import timber.log.Timber
-import java.util.Locale
 import javax.inject.Inject
 import kotlin.math.pow
 
@@ -189,33 +188,30 @@ class MessageTabPresenter @Inject constructor(
     }
 
     private fun calculateMatchRatio(message: Message, query: String): Int {
-        val subjectRatio = FuzzySearch.tokenSortPartialRatio(
-            query.toLowerCase(Locale.getDefault()),
-            message.subject
-        )
+        val subjectRatio = FuzzySearch.tokenSortPartialRatio(query.lowercase(), message.subject)
 
         val senderOrRecipientRatio = FuzzySearch.tokenSortPartialRatio(
-            query.toLowerCase(Locale.getDefault()),
-            if (message.sender.isNotEmpty()) message.sender.toLowerCase(Locale.getDefault())
-            else message.recipient.toLowerCase(Locale.getDefault())
+            query.lowercase(),
+            if (message.sender.isNotEmpty()) message.sender.lowercase()
+            else message.recipient.lowercase()
         )
 
         val dateRatio = listOf(
             FuzzySearch.ratio(
-                query.toLowerCase(Locale.getDefault()),
-                message.date.toFormattedString("dd.MM").toLowerCase(Locale.getDefault())
+                query.lowercase(),
+                message.date.toFormattedString("dd.MM").lowercase()
             ),
             FuzzySearch.ratio(
-                query.toLowerCase(Locale.getDefault()),
-                message.date.toFormattedString("dd.MM.yyyy").toLowerCase(Locale.getDefault())
+                query.lowercase(),
+                message.date.toFormattedString("dd.MM.yyyy").lowercase()
             ),
             FuzzySearch.ratio(
-                query.toLowerCase(Locale.getDefault()),
-                message.date.toFormattedString("d MMMM").toLowerCase(Locale.getDefault())
+                query.lowercase(),
+                message.date.toFormattedString("d MMMM").lowercase()
             ),
             FuzzySearch.ratio(
-                query.toLowerCase(Locale.getDefault()),
-                message.date.toFormattedString("d MMMM yyyy").toLowerCase(Locale.getDefault())
+                query.lowercase(),
+                message.date.toFormattedString("d MMMM yyyy").lowercase()
             )
         ).maxOrNull() ?: 0
 
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/studentinfo/StudentInfoFragment.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/studentinfo/StudentInfoFragment.kt
index 471dc36c..47a64990 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/studentinfo/StudentInfoFragment.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/studentinfo/StudentInfoFragment.kt
@@ -23,6 +23,7 @@ import io.github.wulkanowy.databinding.FragmentStudentInfoBinding
 import io.github.wulkanowy.ui.base.BaseFragment
 import io.github.wulkanowy.ui.modules.main.MainActivity
 import io.github.wulkanowy.ui.modules.main.MainView
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.getThemeAttrColor
 import javax.inject.Inject
 
@@ -149,8 +150,8 @@ class StudentInfoFragment :
     override fun showFamilyTypeData(studentInfo: StudentInfo) {
         updateData(
             listOfNotNull(
-                studentInfo.firstGuardian?.let { it.kinship.capitalize() to it.fullName },
-                studentInfo.secondGuardian?.let { it.kinship.capitalize() to it.fullName },
+                studentInfo.firstGuardian?.let { it.kinship.capitalise() to it.fullName },
+                studentInfo.secondGuardian?.let { it.kinship.capitalise() to it.fullName },
             ).map { (title, value) ->
                 val updatedValue = value.ifBlank { getString(R.string.all_no_data) }
                 val updatedTitle = title.ifBlank { getString(R.string.all_no_data) }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/TimetableDialog.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/TimetableDialog.kt
index f8be9a35..648d9a58 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/TimetableDialog.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/TimetableDialog.kt
@@ -12,10 +12,13 @@ import androidx.fragment.app.DialogFragment
 import io.github.wulkanowy.R
 import io.github.wulkanowy.data.db.entities.Timetable
 import io.github.wulkanowy.databinding.DialogTimetableBinding
+import io.github.wulkanowy.utils.capitalise
+import io.github.wulkanowy.utils.decapitalise
 import io.github.wulkanowy.utils.getThemeAttrColor
 import io.github.wulkanowy.utils.lifecycleAwareVariable
 import io.github.wulkanowy.utils.toFormattedString
 import java.time.LocalDateTime
+import java.util.Locale
 
 class TimetableDialog : DialogFragment() {
 
@@ -101,8 +104,8 @@ class TimetableDialog : DialogFragment() {
                     timetableDialogChangesValue.text = when {
                         canceled && !changes -> "Lekcja odwołana: $info"
                         changes && teacher.isNotBlank() -> "Zastępstwo: $teacher"
-                        changes && teacher.isBlank() -> "Zastępstwo, ${info.decapitalize()}"
-                        else -> info.capitalize()
+                        changes && teacher.isBlank() -> "Zastępstwo, ${info.decapitalise()}"
+                        else -> info.capitalise()
                     }
                 }
                 else -> {
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/TimetablePresenter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/TimetablePresenter.kt
index 1f777f1b..fa1bbfb2 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/TimetablePresenter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/TimetablePresenter.kt
@@ -11,6 +11,7 @@ import io.github.wulkanowy.ui.base.BasePresenter
 import io.github.wulkanowy.ui.base.ErrorHandler
 import io.github.wulkanowy.utils.AnalyticsHelper
 import io.github.wulkanowy.utils.afterLoading
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.flowWithResourceIn
 import io.github.wulkanowy.utils.getLastSchoolDayIfHoliday
 import io.github.wulkanowy.utils.isHolidays
@@ -229,7 +230,7 @@ class TimetablePresenter @Inject constructor(
         view?.apply {
             showPreButton(!currentDate.minusDays(1).isHolidays)
             showNextButton(!currentDate.plusDays(1).isHolidays)
-            updateNavigationDay(currentDate.toFormattedString("EEEE, dd.MM").capitalize())
+            updateNavigationDay(currentDate.toFormattedString("EEEE, dd.MM").capitalise())
         }
     }
 }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/additional/AdditionalLessonsPresenter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/additional/AdditionalLessonsPresenter.kt
index 4edf7b05..3496e141 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/additional/AdditionalLessonsPresenter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/additional/AdditionalLessonsPresenter.kt
@@ -9,6 +9,7 @@ import io.github.wulkanowy.ui.base.BasePresenter
 import io.github.wulkanowy.ui.base.ErrorHandler
 import io.github.wulkanowy.utils.AnalyticsHelper
 import io.github.wulkanowy.utils.afterLoading
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.flowWithResourceIn
 import io.github.wulkanowy.utils.getLastSchoolDayIfHoliday
 import io.github.wulkanowy.utils.isHolidays
@@ -164,7 +165,7 @@ class AdditionalLessonsPresenter @Inject constructor(
         view?.apply {
             showPreButton(!currentDate.minusDays(1).isHolidays)
             showNextButton(!currentDate.plusDays(1).isHolidays)
-            updateNavigationDay(currentDate.toFormattedString("EEEE, dd.MM").capitalize())
+            updateNavigationDay(currentDate.toFormattedString("EEEE, dd.MM").capitalise())
         }
     }
 }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/completed/CompletedLessonsPresenter.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/completed/CompletedLessonsPresenter.kt
index 04e2a5cd..b75b42f8 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/completed/CompletedLessonsPresenter.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/timetable/completed/CompletedLessonsPresenter.kt
@@ -9,6 +9,7 @@ import io.github.wulkanowy.data.repositories.StudentRepository
 import io.github.wulkanowy.ui.base.BasePresenter
 import io.github.wulkanowy.utils.AnalyticsHelper
 import io.github.wulkanowy.utils.afterLoading
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.flowWithResourceIn
 import io.github.wulkanowy.utils.getLastSchoolDayIfHoliday
 import io.github.wulkanowy.utils.isHolidays
@@ -188,7 +189,7 @@ class CompletedLessonsPresenter @Inject constructor(
         view?.apply {
             showPreButton(!currentDate.minusDays(1).isHolidays)
             showNextButton(!currentDate.plusDays(1).isHolidays)
-            updateNavigationDay(currentDate.toFormattedString("EEEE, dd.MM").capitalize())
+            updateNavigationDay(currentDate.toFormattedString("EEEE, dd.MM").capitalise())
         }
     }
 }
diff --git a/app/src/main/java/io/github/wulkanowy/ui/modules/timetablewidget/TimetableWidgetProvider.kt b/app/src/main/java/io/github/wulkanowy/ui/modules/timetablewidget/TimetableWidgetProvider.kt
index fd79f738..733eb17f 100644
--- a/app/src/main/java/io/github/wulkanowy/ui/modules/timetablewidget/TimetableWidgetProvider.kt
+++ b/app/src/main/java/io/github/wulkanowy/ui/modules/timetablewidget/TimetableWidgetProvider.kt
@@ -27,6 +27,7 @@ import io.github.wulkanowy.services.widgets.TimetableWidgetService
 import io.github.wulkanowy.ui.modules.main.MainActivity
 import io.github.wulkanowy.ui.modules.main.MainView
 import io.github.wulkanowy.utils.AnalyticsHelper
+import io.github.wulkanowy.utils.capitalise
 import io.github.wulkanowy.utils.createNameInitialsDrawable
 import io.github.wulkanowy.utils.getCompatColor
 import io.github.wulkanowy.utils.nextOrSameSchoolDay
@@ -180,7 +181,7 @@ class TimetableWidgetProvider : HiltBroadcastReceiver() {
             setEmptyView(R.id.timetableWidgetList, R.id.timetableWidgetEmpty)
             setTextViewText(
                 R.id.timetableWidgetDate,
-                date.toFormattedString("EEEE, dd.MM").capitalize()
+                date.toFormattedString("EEEE, dd.MM").capitalise()
             )
             setTextViewText(
                 R.id.timetableWidgetName,
diff --git a/app/src/main/java/io/github/wulkanowy/utils/AttendanceExtension.kt b/app/src/main/java/io/github/wulkanowy/utils/AttendanceExtension.kt
index f10b00a0..8bccec62 100644
--- a/app/src/main/java/io/github/wulkanowy/utils/AttendanceExtension.kt
+++ b/app/src/main/java/io/github/wulkanowy/utils/AttendanceExtension.kt
@@ -19,7 +19,7 @@ private inline val AttendanceSummary.allAbsences: Double
 fun AttendanceSummary.calculatePercentage() = calculatePercentage(allPresences, allAbsences)
 
 fun List<AttendanceSummary>.calculatePercentage(): Double {
-    return calculatePercentage(sumByDouble { it.allPresences }, sumByDouble { it.allAbsences })
+    return calculatePercentage(sumOf { it.allPresences }, sumOf { it.allAbsences })
 }
 
 private fun calculatePercentage(presence: Double, absence: Double): Double {
diff --git a/app/src/main/java/io/github/wulkanowy/utils/ContextExtension.kt b/app/src/main/java/io/github/wulkanowy/utils/ContextExtension.kt
index f7f56034..be664a47 100644
--- a/app/src/main/java/io/github/wulkanowy/utils/ContextExtension.kt
+++ b/app/src/main/java/io/github/wulkanowy/utils/ContextExtension.kt
@@ -126,7 +126,7 @@ fun Context.createNameInitialsDrawable(
     val firstCharFirstWord = words.getOrNull(0)?.firstOrNull() ?: ""
     val firstCharSecondWord = words.getOrNull(1)?.firstOrNull() ?: ""
 
-    val initials = "$firstCharFirstWord$firstCharSecondWord".toUpperCase()
+    val initials = "$firstCharFirstWord$firstCharSecondWord".uppercase()
 
     val bounds = Rect()
     val dimension = this.dpToPx(64f * scaleFactory).toInt()
diff --git a/app/src/main/java/io/github/wulkanowy/utils/StringExtension.kt b/app/src/main/java/io/github/wulkanowy/utils/StringExtension.kt
index 65167fd7..5c888f30 100644
--- a/app/src/main/java/io/github/wulkanowy/utils/StringExtension.kt
+++ b/app/src/main/java/io/github/wulkanowy/utils/StringExtension.kt
@@ -1,3 +1,9 @@
 package io.github.wulkanowy.utils
 
-inline fun String?.ifNullOrBlank(defaultValue: () -> String) = if (this.isNullOrBlank()) defaultValue() else this
+inline fun String?.ifNullOrBlank(defaultValue: () -> String) =
+    if (isNullOrBlank()) defaultValue() else this
+
+fun String.capitalise() =
+    replaceFirstChar { if (it.isLowerCase()) it.titlecase() else it.toString() }
+
+fun String.decapitalise() = replaceFirstChar { it.lowercase() }
diff --git a/app/src/main/java/io/github/wulkanowy/utils/TimeExtension.kt b/app/src/main/java/io/github/wulkanowy/utils/TimeExtension.kt
index a734b661..b0ec3a71 100644
--- a/app/src/main/java/io/github/wulkanowy/utils/TimeExtension.kt
+++ b/app/src/main/java/io/github/wulkanowy/utils/TimeExtension.kt
@@ -43,7 +43,7 @@ fun Month.getFormattedName(): String {
     val formatter = SimpleDateFormat("LLLL", Locale.getDefault())
 
     val date = now().withMonth(value)
-    return formatter.format(date.toInstant(ZoneOffset.UTC).toEpochMilli()).capitalize()
+    return formatter.format(date.toInstant(ZoneOffset.UTC).toEpochMilli()).capitalise()
 }
 
 inline val LocalDate.nextSchoolDay: LocalDate
diff --git a/build.gradle b/build.gradle
index b91b4b8b..986f626a 100644
--- a/build.gradle
+++ b/build.gradle
@@ -1,6 +1,6 @@
 buildscript {
     ext {
-        kotlin_version = '1.4.32'
+        kotlin_version = '1.5.0'
         about_libraries = '8.8.5'
         hilt_version = "2.35.1"
     }