diff --git a/uhabits-core/src/commonMain/kotlin/org/isoron/platform/time/Dates.kt b/uhabits-core/src/commonMain/kotlin/org/isoron/platform/time/Dates.kt
index 94f415b8a..5a4e369f8 100644
--- a/uhabits-core/src/commonMain/kotlin/org/isoron/platform/time/Dates.kt
+++ b/uhabits-core/src/commonMain/kotlin/org/isoron/platform/time/Dates.kt
@@ -23,6 +23,7 @@ import io.fluidsonic.locale.Locale
 import kotlinx.datetime.Clock
 import kotlinx.datetime.Instant
 import kotlinx.datetime.LocalDateTime
+import kotlinx.datetime.Month
 import kotlinx.datetime.TimeZone
 import kotlinx.datetime.offsetAt
 import kotlinx.datetime.toInstant
@@ -47,7 +48,7 @@ data class LocalDate(val daysSince2000: Int) {
     var monthCache = -1
     var dayCache = -1
 
-    constructor(year: Int, month: Int, day: Int) :
+    constructor(year: Int, month: Month, day: Int) :
         this(daysSince2000(year, month, day))
 
     val dayOfWeek: DayOfWeek
@@ -295,16 +296,16 @@ val nonLeapOffset = arrayOf(
     212, 243, 273, 304, 334, 365
 )
 
-private fun daysSince2000(year: Int, month: Int, day: Int): Int {
+internal fun daysSince2000(year: Int, month: Month, day: Int): Int {
 
     var result = 365 * (year - 2000)
     result += ceil((year - 2000) / 4.0).toInt()
     result -= ceil((year - 2000) / 100.0).toInt()
     result += ceil((year - 2000) / 400.0).toInt()
     result += if (isLeapYear(year)) {
-        leapOffset[month - 1]
+        leapOffset[month.ordinal]
     } else {
-        nonLeapOffset[month - 1]
+        nonLeapOffset[month.ordinal]
     }
     result += (day - 1)
     return result
diff --git a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/time/DatesTest.kt b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/time/DatesTest.kt
index d27599f8f..f036b1c53 100644
--- a/uhabits-core/src/commonTest/kotlin/org/isoron/platform/time/DatesTest.kt
+++ b/uhabits-core/src/commonTest/kotlin/org/isoron/platform/time/DatesTest.kt
@@ -418,6 +418,21 @@ class DatesTest : BaseUnitTest() {
         assertEquals(expected, upcomingTimeMillis)
     }
 
+    @Test
+    fun testDaysSince2000() {
+        val zeroDays =  daysSince2000(2000, Month.JANUARY, 1)
+        assertEquals(0, zeroDays)
+
+        val oneYearWithLeapYear =  daysSince2000(2001, Month.JANUARY, 1)
+        assertEquals(366, oneYearWithLeapYear)
+
+        val fourYearsWithLeapYear =  daysSince2000(2004, Month.JANUARY, 1)
+        assertEquals(1461, fourYearsWithLeapYear)
+
+        val oneYearPrior =  daysSince2000(1999, Month.JANUARY, 1)
+        assertEquals(-365, oneYearPrior)
+    }
+
     private fun unixTime(year: Int, month: Month, day: Int): Long {
         return unixTime(year, month, day, 0, 0)
     }
@@ -434,4 +449,8 @@ class DatesTest : BaseUnitTest() {
             year, month, day, hour, minute, (milliseconds / 1000).toInt(), 0
         ).toInstant(TimeZone.UTC).toEpochMilliseconds()
     }
+
+    companion object {
+        const val JAN_1_2000_IN_UNIX_TIME = 946684800000L
+    }
 }
diff --git a/uhabits-core/src/jvmMain/java/org/isoron/platform/time/JavaDates.kt b/uhabits-core/src/jvmMain/java/org/isoron/platform/time/JavaDates.kt
index b922b88fe..486eaffb6 100644
--- a/uhabits-core/src/jvmMain/java/org/isoron/platform/time/JavaDates.kt
+++ b/uhabits-core/src/jvmMain/java/org/isoron/platform/time/JavaDates.kt
@@ -19,6 +19,7 @@
 
 package org.isoron.platform.time
 
+import kotlinx.datetime.Month
 import java.util.Calendar.DAY_OF_MONTH
 import java.util.Calendar.DAY_OF_WEEK
 import java.util.Calendar.HOUR_OF_DAY
@@ -59,7 +60,7 @@ class JavaLocalDateFormatter(private val locale: Locale) : LocalDateFormatter {
     override fun shortWeekdayName(weekday: DayOfWeek): String {
         val cal = GregorianCalendar()
         cal.set(DAY_OF_WEEK, weekday.daysSinceSunday - 1)
-        return shortWeekdayName(LocalDate(cal.get(YEAR), cal.get(MONTH) + 1, cal.get(DAY_OF_MONTH)))
+        return shortWeekdayName(LocalDate(cal.get(YEAR), Month(cal.get(MONTH) + 1), cal.get(DAY_OF_MONTH)))
     }
 
     override fun shortWeekdayName(date: LocalDate): String {
diff --git a/uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/models/Timestamp.kt b/uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/models/Timestamp.kt
index baa281aeb..39e6d7eb1 100644
--- a/uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/models/Timestamp.kt
+++ b/uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/models/Timestamp.kt
@@ -114,13 +114,6 @@ data class Timestamp(var unixTime: Long) : Comparable<Timestamp> {
             cal[year, javaMonth, day, 0, 0] = 0
             return Timestamp(cal.timeInMillis)
         }
-
-        /**
-         * Given two timestamps, returns whichever timestamp is the oldest one.
-         */
-        fun oldest(first: Timestamp, second: Timestamp): Timestamp {
-            return if (first.unixTime < second.unixTime) first else second
-        }
     }
 
     init {
diff --git a/uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/ui/views/HistoryChart.kt b/uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/ui/views/HistoryChart.kt
index f0da7a196..aa5d4b4fa 100644
--- a/uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/ui/views/HistoryChart.kt
+++ b/uhabits-core/src/jvmMain/java/org/isoron/uhabits/core/ui/views/HistoryChart.kt
@@ -19,6 +19,7 @@
 
 package org.isoron.uhabits.core.ui.views
 
+import kotlinx.datetime.Month
 import org.isoron.platform.gui.Canvas
 import org.isoron.platform.gui.Color
 import org.isoron.platform.gui.DataView
@@ -63,7 +64,7 @@ class HistoryChart(
     private var height = 0.0
     private var nColumns = 0
     private var topLeftOffset = 0
-    private var topLeftDate = LocalDate(2020, 1, 1)
+    private var topLeftDate = LocalDate(2020, Month.JANUARY, 1)
     private var lastPrintedMonth = ""
     private var lastPrintedYear = ""
     private var headerOverflow = 0.0
diff --git a/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/models/TimestampTest.kt b/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/models/TimestampTest.kt
index 8296528b7..9c170d599 100644
--- a/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/models/TimestampTest.kt
+++ b/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/models/TimestampTest.kt
@@ -24,11 +24,22 @@ import org.hamcrest.MatcherAssert.assertThat
 import org.hamcrest.Matchers.equalTo
 import org.hamcrest.Matchers.greaterThan
 import org.hamcrest.Matchers.lessThan
+import org.isoron.platform.time.DatesTest.Companion.JAN_1_2000_IN_UNIX_TIME
+import org.isoron.platform.time.LocalDate
 import org.isoron.uhabits.core.BaseUnitTest
 import org.isoron.uhabits.core.utils.DateUtils.Companion.getToday
 import org.junit.Test
+import java.time.Month
+import kotlin.test.assertEquals
 
 class TimestampTest : BaseUnitTest() {
+    @Test
+    fun testToLocalDate() {
+        val timestamp = Timestamp(JAN_1_2000_IN_UNIX_TIME)
+        val expectedLocalDate = LocalDate(2000, Month.JANUARY ,1)
+        assertEquals(expectedLocalDate, timestamp.toLocalDate())
+    }
+
     @Test
     @Throws(Exception::class)
     fun testCompare() {
diff --git a/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/views/BarChartTest.kt b/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/views/BarChartTest.kt
index ff608a49b..116b8a04d 100644
--- a/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/views/BarChartTest.kt
+++ b/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/views/BarChartTest.kt
@@ -20,6 +20,7 @@
 package org.isoron.uhabits.core.ui.views
 
 import kotlinx.coroutines.runBlocking
+import kotlinx.datetime.Month
 import org.isoron.platform.gui.assertRenders
 import org.isoron.platform.time.JavaLocalDateFormatter
 import org.isoron.platform.time.LocalDate
@@ -28,7 +29,7 @@ import java.util.Locale
 
 class BarChartTest {
     val base = "views/BarChart"
-    val today = LocalDate(2015, 1, 25)
+    val today = LocalDate(2015, Month.JANUARY, 25)
     private val fmt = JavaLocalDateFormatter(Locale.US)
     val theme = LightTheme()
     val component = BarChart(theme, fmt)
diff --git a/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/views/HistoryChartTest.kt b/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/views/HistoryChartTest.kt
index a53135f9b..b309d4550 100644
--- a/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/views/HistoryChartTest.kt
+++ b/uhabits-core/src/jvmTest/java/org/isoron/uhabits/core/ui/views/HistoryChartTest.kt
@@ -24,6 +24,7 @@ import com.nhaarman.mockitokotlin2.reset
 import com.nhaarman.mockitokotlin2.verify
 import com.nhaarman.mockitokotlin2.verifyNoMoreInteractions
 import kotlinx.coroutines.runBlocking
+import kotlinx.datetime.Month
 import org.isoron.platform.gui.assertRenders
 import org.isoron.platform.time.DayOfWeek
 import org.isoron.platform.time.DayOfWeek.SUNDAY
@@ -43,7 +44,7 @@ class HistoryChartTest {
     private val dateClickedListener: OnDateClickedListener = mock()
 
     val view = HistoryChart(
-        today = LocalDate(2015, 1, 25),
+        today = LocalDate(2015, Month.JANUARY, 25),
         paletteColor = PaletteColor(7),
         theme = LightTheme(),
         dateFormatter = JavaLocalDateFormatter(Locale.US),
@@ -86,20 +87,20 @@ class HistoryChartTest {
 
         // Click top left date
         view.onClick(20.0, 46.0)
-        verify(dateClickedListener).onDateClicked(LocalDate(2014, 10, 26))
+        verify(dateClickedListener).onDateClicked(LocalDate(2014, Month.OCTOBER, 26))
         reset(dateClickedListener)
         view.onClick(2.0, 28.0)
-        verify(dateClickedListener).onDateClicked(LocalDate(2014, 10, 26))
+        verify(dateClickedListener).onDateClicked(LocalDate(2014, Month.OCTOBER, 26))
         reset(dateClickedListener)
 
         // Click date in the middle
         view.onClick(163.0, 113.0)
-        verify(dateClickedListener).onDateClicked(LocalDate(2014, 12, 10))
+        verify(dateClickedListener).onDateClicked(LocalDate(2014, Month.DECEMBER, 10))
         reset(dateClickedListener)
 
         // Click today
         view.onClick(336.0, 37.0)
-        verify(dateClickedListener).onDateClicked(LocalDate(2015, 1, 25))
+        verify(dateClickedListener).onDateClicked(LocalDate(2015, Month.JANUARY, 25))
         reset(dateClickedListener)
 
         // Click header