diff --git a/build.sbt b/build.sbt
index ecc3192..d803aa4 100644
--- a/build.sbt
+++ b/build.sbt
@@ -1,7 +1,7 @@
 
 // Our Scala versions.
-lazy val `scala-3.0`      = "3.0.0-RC2"
-lazy val `scala-3.0-prev` = "3.0.0-RC1"
+lazy val `scala-3.0`      = "3.0.0-RC3"
+lazy val `scala-3.0-prev` = "3.0.0-RC2"
 lazy val `scala-2.12`     = "2.12.12"
 lazy val `scala-2.13`     = "2.13.5"
 
@@ -35,15 +35,15 @@ Compile / doc     / scalacOptions ++= Seq(
 )
 
 // MUnit
-libraryDependencies += "org.scalameta" %% "munit" % "0.7.23" % Test
+libraryDependencies += "org.scalameta" %% "munit" % "0.7.25" % Test
 testFrameworks += new TestFramework("munit.Framework")
 
 // Scala 2 needs scala-reflect
-libraryDependencies ++= Seq("org.scala-lang" % "scala-reflect" % scalaVersion.value).filterNot(_ => isDotty.value)
+libraryDependencies ++= Seq("org.scala-lang" % "scala-reflect" % scalaVersion.value).filterNot(_ => scalaVersion.value.startsWith("3."))
 
 // Add some more source directories
-unmanagedSourceDirectories in Compile ++= {
-  val sourceDir = (sourceDirectory in Compile).value
+Compile / unmanagedSourceDirectories ++= {
+  val sourceDir = (Compile / sourceDirectory).value
   CrossVersion.partialVersion(scalaVersion.value) match {
     case Some((3, _))  => Seq(sourceDir / "scala-3")
     case Some((2, _))  => Seq(sourceDir / "scala-2")
@@ -52,8 +52,8 @@ unmanagedSourceDirectories in Compile ++= {
 }
 
 // Also for test
-unmanagedSourceDirectories in Test ++= {
-  val sourceDir = (sourceDirectory in Test).value
+Test / unmanagedSourceDirectories ++= {
+  val sourceDir = (Test / sourceDirectory).value
   CrossVersion.partialVersion(scalaVersion.value) match {
     case Some((3, _))  => Seq(sourceDir / "scala-3")
     case Some((2, _))  => Seq(sourceDir / "scala-2")
@@ -64,7 +64,7 @@ unmanagedSourceDirectories in Test ++= {
 // dottydoc really doesn't work at all right now
 Compile / doc / sources := {
   val old = (Compile / doc / sources).value
-  if (isDotty.value)
+  if (scalaVersion.value.startsWith("3."))
     Seq()
   else
     old
diff --git a/project/build.properties b/project/build.properties
index d91c272..e67343a 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1 +1 @@
-sbt.version=1.4.6
+sbt.version=1.5.0
diff --git a/project/plugins.sbt b/project/plugins.sbt
index 0fb3bbb..947a90a 100644
--- a/project/plugins.sbt
+++ b/project/plugins.sbt
@@ -1,10 +1,4 @@
 addSbtPlugin("com.geirsson"              % "sbt-ci-release" % "1.5.7")
 addSbtPlugin("de.heikoseeberger"         % "sbt-header"     % "5.6.0")
-addSbtPlugin("com.lightbend.paradox"     % "sbt-paradox"    % "0.9.2")
-addSbtPlugin("com.typesafe.sbt"          % "sbt-site"       % "1.4.1")
-addSbtPlugin("com.typesafe.sbt"          % "sbt-ghpages"    % "0.6.3")
-addSbtPlugin("com.timushev.sbt"          % "sbt-updates"    % "0.5.2")
+addSbtPlugin("com.timushev.sbt"          % "sbt-updates"    % "0.5.3")
 addSbtPlugin("io.github.davidgregory084" % "sbt-tpolecat"   % "0.1.17")
-addSbtPlugin("org.scalameta"             % "sbt-mdoc"       % "2.2.19")
-addSbtPlugin("org.scoverage"             % "sbt-scoverage"  % "1.6.1")
-addSbtPlugin("ch.epfl.lamp"              % "sbt-dotty"      % "0.5.4")
diff --git a/project/project/plugins.sbt b/project/project/plugins.sbt
index aa4d3f0..2e5f876 100644
--- a/project/project/plugins.sbt
+++ b/project/project/plugins.sbt
@@ -1 +1 @@
-addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.5.2")
+addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.5.3")