Unable to Upgrade Play

I am attempting to upgrade (Scala) Play Framework from 2.6.x to 2.7.x (with the goal of ultimately upgrading to 2.8.x). When I upgrade SBT to 1.3.5 in build.properties, I get a bunch of warnings about fetches over http and the error at the bottom:

[info] Loading global plugins from /Users/Neil/.sbt/1.0/plugins
[warn] insecure HTTP request is deprecated 'http://repo.typesafe.com/typesafe/releases'; switch to HTTPS or opt-in as ("typesafe-releases" at "http://repo.typesafe.com/typesafe/releases").withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'http://repo.typesafe.com/typesafe/releases'; switch to HTTPS or opt-in as ("typesafe-releases" at "http://repo.typesafe.com/typesafe/releases").withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'http://repo.typesafe.com/typesafe/releases'; switch to HTTPS or opt-in as ("typesafe-releases" at "http://repo.typesafe.com/typesafe/releases").withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("typesafe-ivy-releasez", url(...)).withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("typesafe-ivy-releasez", url(...)).withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("typesafe-ivy-releasez", url(...)).withAllowInsecureProtocol(true)
[info] Loading settings for project ninaday-build from activator-sbt-eclipse-shim.sbt,plugins.sbt,activator-sbt-idea-shim.sbt ...
[info] Loading project definition from /Users/Neil/Vidya/applications/ninaday/project
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://dl.bintray.com/heroku/sbt-plugins/[organisation]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)([branch]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://dl.bintray.com/heroku/sbt-plugins/[organisation]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)([branch]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("heroku-sbt-plugin-releases", url(...)).withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'http://repo.typesafe.com/typesafe/releases'; switch to HTTPS or opt-in as ("typesafe-releases" at "http://repo.typesafe.com/typesafe/releases").withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'http://repo.typesafe.com/typesafe/releases'; switch to HTTPS or opt-in as ("typesafe-releases" at "http://repo.typesafe.com/typesafe/releases").withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("typesafe-ivy-releasez", url(...)).withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("typesafe-ivy-releasez", url(...)).withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://dl.bintray.com/heroku/sbt-plugins/[organisation]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)([branch]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://dl.bintray.com/heroku/sbt-plugins/[organisation]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)([branch]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("heroku-sbt-plugin-releases", url(...)).withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://dl.bintray.com/heroku/sbt-plugins/[organisation]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)([branch]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://dl.bintray.com/heroku/sbt-plugins/[organisation]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)([branch]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("heroku-sbt-plugin-releases", url(...)).withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'http://repo.typesafe.com/typesafe/releases'; switch to HTTPS or opt-in as ("typesafe-releases" at "http://repo.typesafe.com/typesafe/releases").withAllowInsecureProtocol(true)
[warn] insecure HTTP request is deprecated 'Patterns(ivyPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), artifactPatterns=Vector(http://repo.typesafe.com/typesafe/ivy-releases/[organization]/[module]/(scala_[scalaVersion]/)(sbt_[sbtVersion]/)[revision]/[type]s/[artifact](-[classifier]).[ext]), isMavenCompatible=false, descriptorOptional=false, skipConsistencyCheck=false)'; switch to HTTPS or opt-in as Resolver.url("typesafe-ivy-releasez", url(...)).withAllowInsecureProtocol(true)
[warn]
[warn] 	Note: Some unresolved dependencies have extra attributes.  Check that these dependencies exist with the requested attributes.
[warn] 		com.typesafe.play:sbt-plugin:2.7.4 (sbtVersion=1.0, scalaVersion=2.12)
[warn]
[warn] 	Note: Unresolved dependencies path:
[error] sbt.librarymanagement.ResolveException: Error downloading com.typesafe.play:sbt-plugin;sbtVersion=1.0;scalaVersion=2.12:2.7.4
[error]   Not found
[error]   Not found
[error]   not found: https://repo1.maven.org/maven2/com/typesafe/play/sbt-plugin_2.12_1.0/2.7.4/sbt-plugin-2.7.4.pom
[error]   not found: /Users/Neil/.ivy2/local/com.typesafe.play/sbt-plugin/scala_2.12/sbt_1.0/2.7.4/ivys/ivy.xml
[error]   not found: /Users/Neil/.activator/repository/com.typesafe.play/sbt-plugin/scala_2.12/sbt_1.0/2.7.4/ivys/ivy.xml
[error]   not found: /usr/local/activator-1.3.6/repository/com.typesafe.play/sbt-plugin/scala_2.12/sbt_1.0/2.7.4/ivys/ivy.xml
[error]   not found: http://dl.bintray.com/heroku/sbt-plugins/com.typesafe.play/sbt-plugin/scala_2.12/sbt_1.0/2.7.4/ivys/ivy.xml
[error]   not found: https://dl.bintray.com/neomaclin/maven/com/typesafe/play/sbt-plugin_2.12_1.0/2.7.4/sbt-plugin-2.7.4.pom
[error]   download error: Caught javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target (sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target) while downloading https://repo.scala-sbt.org/scalasbt/sbt-plugin-releases/com.typesafe.play/sbt-plugin/scala_2.12/sbt_1.0/2.7.4/ivys/ivy.xml

Resolvers are as follows:

resolvers += Resolver.typesafeIvyRepo("releases")
resolvers += Resolver.sbtPluginRepo("releases")
resolvers += Resolver.url("heroku-sbt-plugin-releases", url("http://dl.bintray.com/heroku/sbt-plugins/"))(Resolver.ivyStylePatterns)

I am not behind a proxy. Any ideas about the issue?

The above is an indication of an untrusted CA. That mostly means an outdated CA, or a intercepting HTTP proxy in between.

Thank you for your response. I am aware that is the proximate cause of the problem, but we have both identified the symptom rather than the disease.

As it turns out, the issue is with the version of the JDK IntelliJ was using to build Play. I still haven’t worked through all the issues as it turns out there are a lot more moving parts in upgrading Play than I realized (between SBT version, system JDK version running SBT, IntelliJ version, IntelliJ JDK version, Akka versions, etc.) that has made the entire process super difficult, but I have solved this PKIX problem at least.

Thanks again.