diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 5dfa54c7f..7668d23db 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,6 +17,8 @@ jobs:
         include:
           - scalaversion: "2.10.7"
             scalajsversion: "0.6.x"
+          - scalaversion: "3.0.1"
+            scalajsversion: "1.x"
     env:
       SCALAJS_VERSION: "${{ matrix.scalajsversion == '0.6.x' && '0.6.28' || '' }}"
     steps:
diff --git a/build.sbt b/build.sbt
index 371ebc4c8..5fe801501 100644
--- a/build.sbt
+++ b/build.sbt
@@ -5,11 +5,11 @@ lazy val root = project.in(file(".")).
 
 name := "Scala.js DOM"
 
-crossScalaVersions in ThisBuild := {
-  if (scalaJSVersion.startsWith("1.")) Seq("2.12.10", "2.11.12", "2.13.1")
+ThisBuild / crossScalaVersions := {
+  if (scalaJSVersion.startsWith("1.")) Seq("2.12.10", "2.11.12", "2.13.1", "3.0.1")
   else Seq("2.12.10", "2.11.12", "2.10.7", "2.13.1")
 }
-scalaVersion in ThisBuild := crossScalaVersions.value.head
+ThisBuild / scalaVersion := crossScalaVersions.value.head
 
 val commonSettings = Seq(
   version := "1.2.0-SNAPSHOT",
@@ -104,7 +104,7 @@ lazy val readme = ScalatexReadme(
 ).settings(
   scalaVersion := "2.12.10",
   scalacOptions ++= Seq("-deprecation", "-feature", "-Xfatal-warnings"),
-  (resources in Compile) += (fullOptJS in (example, Compile)).value.data
+  (Compile / resources) += (example / Compile / fullOptJS).value.data
 )
 
 lazy val example = project.
diff --git a/project/build.properties b/project/build.properties
index c0bab0494..10fd9eee0 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.2.8
+sbt.version=1.5.5
diff --git a/project/build.sbt b/project/build.sbt
index bc96d108b..91d1d968a 100644
--- a/project/build.sbt
+++ b/project/build.sbt
@@ -1,5 +1,5 @@
 val scalaJSVersion =
-  Option(System.getenv("SCALAJS_VERSION")).filter(_ != "").getOrElse("1.0.0")
+  Option(System.getenv("SCALAJS_VERSION")).filter(_ != "").getOrElse("1.5.0")
 
 addSbtPlugin("org.scala-js" % "sbt-scalajs" % scalaJSVersion)
 
diff --git a/src/main/scala/org/scalajs/dom/crypto/Crypto.scala b/src/main/scala/org/scalajs/dom/crypto/Crypto.scala
index e411dfc51..b3732ebc1 100644
--- a/src/main/scala/org/scalajs/dom/crypto/Crypto.scala
+++ b/src/main/scala/org/scalajs/dom/crypto/Crypto.scala
@@ -930,10 +930,8 @@ object KeyFormat {
 trait RSAPublicKey extends js.Object {
 
   /* modulus, as a base64 URL encoded String */
-  @js.native
   def n: String = js.native
 
   /* exponent, as a base64 URL encoded String */
-  @js.native
   def e: String = js.native
 }
diff --git a/src/main/scala/org/scalajs/dom/experimental/intl/Intl.scala b/src/main/scala/org/scalajs/dom/experimental/intl/Intl.scala
index e80f410c8..f0c99b381 100644
--- a/src/main/scala/org/scalajs/dom/experimental/intl/Intl.scala
+++ b/src/main/scala/org/scalajs/dom/experimental/intl/Intl.scala
@@ -123,12 +123,12 @@ object CollatorOptions {
   ): CollatorOptions = {
     js.Dynamic
       .literal(
-          localeMatcher = localeMatcher,
-          usage = usage,
-          sensitivity = sensitivity,
-          ignorePunctuation = ignorePunctuation,
-          numeric = numeric,
-          caseFirst = caseFirst
+          localeMatcher = localeMatcher.asInstanceOf[js.Any],
+          usage = usage.asInstanceOf[js.Any],
+          sensitivity = sensitivity.asInstanceOf[js.Any],
+          ignorePunctuation = ignorePunctuation.asInstanceOf[js.Any],
+          numeric = numeric.asInstanceOf[js.Any],
+          caseFirst = caseFirst.asInstanceOf[js.Any]
       )
       .asInstanceOf[CollatorOptions]
   }
@@ -200,19 +200,19 @@ object DateTimeFormatOptions {
     // format: off
     js.Dynamic
       .literal(
-          localeMatcher = localeMatcher,
-          timeZone = timeZone,
-          hour12 = hour12,
-          formatMatcher = formatMatcher,
-          weekday = weekday,
-          era = era,
-          year = year,
-          month = month,
-          day = day,
-          hour = hour,
-          minute = minute,
-          second = second,
-          timeZoneName = timeZoneName
+          localeMatcher = localeMatcher.asInstanceOf[js.Any],
+          timeZone = timeZone.asInstanceOf[js.Any],
+          hour12 = hour12.asInstanceOf[js.Any],
+          formatMatcher = formatMatcher.asInstanceOf[js.Any],
+          weekday = weekday.asInstanceOf[js.Any],
+          era = era.asInstanceOf[js.Any],
+          year = year.asInstanceOf[js.Any],
+          month = month.asInstanceOf[js.Any],
+          day = day.asInstanceOf[js.Any],
+          hour = hour.asInstanceOf[js.Any],
+          minute = minute.asInstanceOf[js.Any],
+          second = second.asInstanceOf[js.Any],
+          timeZoneName = timeZoneName.asInstanceOf[js.Any]
       )
       .asInstanceOf[DateTimeFormatOptions]
     // format: on
@@ -300,16 +300,16 @@ object NumberFormatOptions {
   ): NumberFormatOptions = {
     js.Dynamic
       .literal(
-          localeMatcher = localeMatcher,
-          style = style,
-          currency = currency,
-          currencyDisplay = currencyDisplay,
-          useGrouping = useGrouping,
-          minimumIntegerDigits = minimumIntegerDigits,
-          minimumFractionDigits = minimumFractionDigits,
-          maximumFractionDigits = maximumFractionDigits,
-          minimumSignificantDigits = minimumSignificantDigits,
-          maximumSignificantDigits = maximumSignificantDigits
+          localeMatcher = localeMatcher.asInstanceOf[js.Any],
+          style = style.asInstanceOf[js.Any],
+          currency = currency.asInstanceOf[js.Any],
+          currencyDisplay = currencyDisplay.asInstanceOf[js.Any],
+          useGrouping = useGrouping.asInstanceOf[js.Any],
+          minimumIntegerDigits = minimumIntegerDigits.asInstanceOf[js.Any],
+          minimumFractionDigits = minimumFractionDigits.asInstanceOf[js.Any],
+          maximumFractionDigits = maximumFractionDigits.asInstanceOf[js.Any],
+          minimumSignificantDigits = minimumSignificantDigits.asInstanceOf[js.Any],
+          maximumSignificantDigits = maximumSignificantDigits.asInstanceOf[js.Any]
       )
       .asInstanceOf[NumberFormatOptions]
   }
diff --git a/src/main/scala/org/scalajs/dom/ext/package.scala b/src/main/scala/org/scalajs/dom/ext/package.scala
index 90e848b21..19e5aebff 100644
--- a/src/main/scala/org/scalajs/dom/ext/package.scala
+++ b/src/main/scala/org/scalajs/dom/ext/package.scala
@@ -22,17 +22,20 @@ package object ext {
     def cast[T] = x.asInstanceOf[T]
   }
 
-  implicit def pimpAnimatedNumber(x: svg.AnimatedNumber) = x.baseVal
+  implicit def pimpAnimatedNumber(x: svg.AnimatedNumber): Double = x.baseVal
 
-  implicit def pimpRichAnimatedNumber(x: svg.AnimatedNumber) =
+  implicit def pimpRichAnimatedNumber(
+      x: svg.AnimatedNumber): runtime.RichDouble =
     x.baseVal: runtime.RichDouble
 
-  implicit def pimpAnimatedLength(x: svg.AnimatedLength) = x.baseVal.value
+  implicit def pimpAnimatedLength(x: svg.AnimatedLength): Double =
+    x.baseVal.value
 
-  implicit def pimpRichAnimatedLength(x: svg.AnimatedLength) =
+  implicit def pimpRichAnimatedLength(
+      x: svg.AnimatedLength): runtime.RichDouble =
     x.baseVal.value: runtime.RichDouble
 
-  implicit def color2String(c: Color) = c.toString
+  implicit def color2String(c: Color): String = c.toString
   implicit class pimpedContext(val ctx: CanvasRenderingContext2D) {
     def prepCircle(x: Double, y: Double, r: Double) = {
       ctx.beginPath()