scalacReleaseOption and javacReleaseOption

build.sbt

@@ -22,7 +22,8 @@ lazy val commonSettings = Seq(
       case Some((2, 11)) => Seq()
       case _ => sys.error("Unsupported scala version")
     }
-  },
+  } ++ scalacReleaseOption,
+  javacOptions ++= javacReleaseOption,
   resolvers += Resolver.sonatypeRepo("public"),
   licenses := Seq("CC0" -> url("https://creativecommons.org/publicdomain/zero/1.0/legalcode")),
   homepage := Some(url("https://github.com/ScorexFoundation/sigmastate-interpreter")),
@@ -55,6 +56,22 @@ lazy val commonSettings = Seq(
   ),
 )
 
+def scalacReleaseOption = {
+  if (System.getProperty("java.version").startsWith("1."))
+  // java <9 "-release" is not supported
+    Seq()
+  else
+    Seq("-release", "8") // this is passed to javac as `javac -release 8`
+}
+
+def javacReleaseOption = {
+  if (System.getProperty("java.version").startsWith("1."))
+  // java <9 "--release" is not supported
+    Seq()
+  else
+    Seq("--release", "8")
+}
+
 // suffix version with "-SNAPSHOT" for builds without a git tag
 dynverSonatypeSnapshots in ThisBuild := true
 // use "-" instead of default "+"