diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index f3bb605bb8..8a6ceff8fd 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -296,6 +296,13 @@ source "$HOMEBREW_LIBRARY/Homebrew/utils/analytics.sh"
 setup-analytics
 report-analytics-screenview-command
 
+# Let user know we're still updating Homebrew if brew update --preinstall
+# exceeds 3 seconds.
+update-preinstall-timer() {
+  sleep 3
+  echo 'Updating Homebrew...' >&2
+}
+
 update-preinstall() {
   [[ -z "$HOMEBREW_HELP" ]] || return
   [[ -z "$HOMEBREW_NO_AUTO_UPDATE" ]] || return
@@ -306,7 +313,19 @@ update-preinstall() {
 
   if [[ "$HOMEBREW_COMMAND" = "install" || "$HOMEBREW_COMMAND" = "upgrade" || "$HOMEBREW_COMMAND" = "tap" ]]
   then
+    if [[ -z "$HOMEBREW_VERBOSE" ]]
+    then
+      update-preinstall-timer &
+      timer_pid=$!
+    fi
+
     brew update --preinstall
+
+    if [[ -n "$timer_pid" ]]
+    then
+      kill "$timer_pid" 2>/dev/null
+      wait "$timer_pid" 2>/dev/null
+    fi
   fi
 
   # If brew update --preinstall did a migration then export the new locations.
diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index 0867e893ad..16639c4aac 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -142,6 +142,7 @@ module Homebrew
           msg = "#{current.full_name}-#{current.installed_version} already installed"
           unless current.linked_keg.symlink? || current.keg_only?
             msg << ", it's just not linked"
+            puts "You can link formula with `brew link #{f}`"
           end
           opoo msg
         elsif f.migration_needed? && !ARGV.force?
@@ -222,25 +223,12 @@ module Homebrew
 
   def check_development_tools
     checks = Diagnostic::Checks.new
-    all_development_tools_checks = checks.development_tools_checks +
-                                   checks.fatal_development_tools_checks
-    all_development_tools_checks.each do |check|
+    checks.fatal_development_tools_checks.each do |check|
       out = checks.send(check)
       next if out.nil?
-      if checks.fatal_development_tools_checks.include?(check)
-        odie out
-      else
-        opoo out
-      end
+      ofail out
     end
-  end
-
-  def check_macports
-    return if MacOS.macports_or_fink.empty?
-
-    opoo "It appears you have MacPorts or Fink installed."
-    puts "Software installed with other package managers causes known problems for"
-    puts "Homebrew. If a formula fails to build, uninstall MacPorts/Fink and try again."
+    exit 1 if Homebrew.failed?
   end
 
   def check_cellar
@@ -282,8 +270,5 @@ module Homebrew
     # another formula. In that case, don't generate an error, just move on.
   rescue CannotInstallFormulaError => e
     ofail e.message
-  rescue BuildError
-    check_macports
-    raise
   end
 end
diff --git a/Library/Homebrew/cmd/update-report.rb b/Library/Homebrew/cmd/update-report.rb
index 72dcc293de..9d096c4cbb 100644
--- a/Library/Homebrew/cmd/update-report.rb
+++ b/Library/Homebrew/cmd/update-report.rb
@@ -415,7 +415,7 @@ class Reporter
 
       # This means it is a Cask
       if report[:DC].include? full_name
-        next unless (HOMEBREW_REPOSITORY/"Caskroom"/name).exist?
+        next unless (HOMEBREW_PREFIX/"Caskroom"/name).exist?
         new_tap = Tap.fetch(new_tap_name)
         new_tap.install unless new_tap.installed?
         ohai "#{name} has been moved to Homebrew.", <<-EOS.undent
@@ -442,7 +442,7 @@ class Reporter
       new_tap = Tap.fetch(new_tap_name)
       # For formulae migrated to cask: Auto-install cask or provide install instructions.
       if new_tap_name == "caskroom/cask"
-        if new_tap.installed? && (HOMEBREW_REPOSITORY/"Caskroom").directory?
+        if new_tap.installed? && (HOMEBREW_PREFIX/"Caskroom").directory?
           ohai "#{name} has been moved to Homebrew-Cask."
           ohai "brew uninstall --force #{name}"
           system HOMEBREW_BREW_FILE, "uninstall", "--force", name
diff --git a/Library/Homebrew/dev-cmd/bottle.rb b/Library/Homebrew/dev-cmd/bottle.rb
index b1a3ebb431..7e98f2ebb1 100644
--- a/Library/Homebrew/dev-cmd/bottle.rb
+++ b/Library/Homebrew/dev-cmd/bottle.rb
@@ -251,6 +251,8 @@ module Homebrew
           relocatable = false if keg_contain?(cellar, keg, ignores)
           if prefix != prefix_check
             relocatable = false if keg_contain_absolute_symlink_starting_with?(prefix, keg)
+            relocatable = false if keg_contain?("#{prefix}/etc", keg, ignores)
+            relocatable = false if keg_contain?("#{prefix}/var", keg, ignores)
           end
           skip_relocation = relocatable && !keg.require_relocation?
         end
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index fbc10fe208..e499c4d3b8 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -86,12 +86,17 @@ module Homebrew
       def development_tools_checks
         %w[
           check_for_installed_developer_tools
-        ]
+        ].freeze
       end
 
       def fatal_development_tools_checks
         %w[
-        ]
+        ].freeze
+      end
+
+      def build_error_checks
+        (development_tools_checks + %w[
+        ]).freeze
       end
 
       def check_for_installed_developer_tools
@@ -172,6 +177,7 @@ module Homebrew
           "libUFSDExtFS.dylib", # Paragon ExtFS
           "libecomlodr.dylib", # Symantec Endpoint Protection
           "libsymsea.*.dylib", # Symantec Endpoint Protection
+          "sentinel.dylib", # SentinelOne
         ]
 
         __check_stray_files "/usr/local/lib", "*.dylib", white_list, <<-EOS.undent
diff --git a/Library/Homebrew/exceptions.rb b/Library/Homebrew/exceptions.rb
index 7aecbe494f..3d9b24034f 100644
--- a/Library/Homebrew/exceptions.rb
+++ b/Library/Homebrew/exceptions.rb
@@ -327,22 +327,9 @@ class BuildError < RuntimeError
   end
 
   def dump
-    if !ARGV.verbose?
-      puts
-      puts Formatter.error(Formatter.url(OS::ISSUES_URL), label: "READ THIS")
-      if formula.tap
-        case formula.tap.name
-        when "homebrew/boneyard"
-          puts "#{formula} was moved to homebrew-boneyard because it has unfixable issues."
-          puts "Please do not file any issues about this. Sorry!"
-        else
-          if issues_url = formula.tap.issues_url
-            puts "If reporting this issue please do so at (not Homebrew/brew):"
-            puts "  #{Formatter.url(issues_url)}"
-          end
-        end
-      end
-    else
+    puts
+
+    if ARGV.verbose?
       require "system_config"
       require "build_environment"
 
@@ -360,15 +347,50 @@ class BuildError < RuntimeError
         puts logs.map { |fn| "     #{fn}" }.join("\n")
       end
     end
+
+    if formula.tap && formula.tap.name == "homebrew/boneyard"
+      onoe <<-EOS.undent
+        #{formula} was moved to homebrew-boneyard because it has unfixable issues.
+        Please do not file any issues about this. Sorry!
+      EOS
+      return
+    end
+
+    if formula.tap
+      if formula.tap.official?
+        puts Formatter.error(Formatter.url(OS::ISSUES_URL), label: "READ THIS")
+      elsif issues_url = formula.tap.issues_url
+        puts <<-EOS.undent
+          If reporting this issue please do so at (not Homebrew/brew or Homebrew/core):
+          #{Formatter.url(issues_url)}
+        EOS
+      else
+        puts <<-EOS.undent
+          If reporting this issue please do so to (not Homebrew/brew or Homebrew/core):
+          #{formula.tap}
+        EOS
+      end
+    else
+      puts <<-EOS.undent
+        Do not report this issue to Homebrew/brew or Homebrew/core!
+      EOS
+    end
+
     puts
+
     if issues && !issues.empty?
       puts "These open issues may also help:"
       puts issues.map { |i| "#{i["title"]} #{i["html_url"]}" }.join("\n")
     end
 
     require "diagnostic"
-    unsupported_macos = Homebrew::Diagnostic::Checks.new.check_for_unsupported_macos
-    opoo unsupported_macos if unsupported_macos
+    checks = Homebrew::Diagnostic::Checks.new
+    checks.build_error_checks.each do |check|
+      out = checks.send(check)
+      next if out.nil?
+      puts
+      ofail out
+    end
   end
 end
 
diff --git a/Library/Homebrew/extend/os/mac/diagnostic.rb b/Library/Homebrew/extend/os/mac/diagnostic.rb
index 0ac95bfd98..0f37e8af57 100644
--- a/Library/Homebrew/extend/os/mac/diagnostic.rb
+++ b/Library/Homebrew/extend/os/mac/diagnostic.rb
@@ -10,19 +10,23 @@ module Homebrew
           check_xcode_license_approved
           check_for_osx_gcc_installer
           check_xcode_8_without_clt_on_el_capitan
-        ]
+          check_xcode_up_to_date
+          check_clt_up_to_date
+          check_for_other_package_managers
+        ].freeze
       end
 
       def fatal_development_tools_checks
-        if MacOS.version >= :sierra && ENV["CI"].nil?
-          %w[
-            check_xcode_up_to_date
-            check_clt_up_to_date
-          ]
-        else
-          %w[
-          ]
-        end
+        %w[
+          check_xcode_minimum_version
+          check_clt_minimum_version
+        ].freeze
+      end
+
+      def build_error_checks
+        (development_tools_checks + %w[
+          check_for_unsupported_macos
+        ]).freeze
       end
 
       def check_for_unsupported_macos
@@ -62,7 +66,8 @@ module Homebrew
       end
 
       def check_xcode_up_to_date
-        return unless MacOS::Xcode.installed? && MacOS::Xcode.outdated?
+        return unless MacOS::Xcode.installed?
+        return unless MacOS::Xcode.outdated?
 
         message = <<-EOS.undent
           Your Xcode (#{MacOS::Xcode.version}) is outdated.
@@ -83,7 +88,8 @@ module Homebrew
       end
 
       def check_clt_up_to_date
-        return unless MacOS::CLT.installed? && MacOS::CLT.outdated?
+        return unless MacOS::CLT.installed?
+        return unless MacOS::CLT.outdated?
 
         <<-EOS.undent
           A newer Command Line Tools release is available.
@@ -94,7 +100,8 @@ module Homebrew
       def check_xcode_8_without_clt_on_el_capitan
         return unless MacOS::Xcode.without_clt?
         # Scope this to Xcode 8 on El Cap for now
-        return unless MacOS.version == :el_capitan && MacOS::Xcode.version >= "8"
+        return unless MacOS.version == :el_capitan
+        return unless MacOS::Xcode.version >= "8"
 
         <<-EOS.undent
           You have Xcode 8 installed without the CLT;
@@ -104,6 +111,27 @@ module Homebrew
         EOS
       end
 
+      def check_xcode_minimum_version
+        return unless MacOS::Xcode.installed?
+        return unless MacOS::Xcode.minimum_version?
+
+        <<-EOS.undent
+          Your Xcode (#{MacOS::Xcode.version}) is too outdated.
+          Please update to Xcode #{MacOS::Xcode.latest_version} (or delete it).
+          #{MacOS::Xcode.update_instructions}
+        EOS
+      end
+
+      def check_clt_minimum_version
+        return unless MacOS::CLT.installed?
+        return unless MacOS::CLT.minimum_version?
+
+        <<-EOS.undent
+          Your Command Line Tools are too outdated.
+          #{MacOS::CLT.update_instructions}
+        EOS
+      end
+
       def check_for_osx_gcc_installer
         return unless MacOS.version < "10.7" || ((MacOS::Xcode.version || "0") > "4.1")
         return unless DevelopmentTools.clang_version == "2.1"
diff --git a/Library/Homebrew/extend/os/mac/utils/bottles.rb b/Library/Homebrew/extend/os/mac/utils/bottles.rb
index 0dd7341ea1..18312c9fa8 100644
--- a/Library/Homebrew/extend/os/mac/utils/bottles.rb
+++ b/Library/Homebrew/extend/os/mac/utils/bottles.rb
@@ -38,7 +38,6 @@ module Utils
 
       # Allows a bottle tag to specify a specific OS or later,
       # so the same bottle can target multiple OSs.
-      # Not used in core, used in taps.
       def find_or_later_tag(tag)
         begin
           tag_version = MacOS::Version.from_symbol(tag)
diff --git a/Library/Homebrew/formulary.rb b/Library/Homebrew/formulary.rb
index 5ce09f6ba5..4d6832e44f 100644
--- a/Library/Homebrew/formulary.rb
+++ b/Library/Homebrew/formulary.rb
@@ -159,6 +159,11 @@ class Formulary
     attr_reader :tap
 
     def initialize(tapped_name)
+      name, path = formula_name_path(tapped_name)
+      super name, path
+    end
+
+    def formula_name_path(tapped_name, warn: true)
       user, repo, name = tapped_name.split("/", 3).map(&:downcase)
       @tap = Tap.fetch user, repo
       formula_dir = @tap.formula_dir || @tap.path
@@ -170,12 +175,25 @@ class Formulary
           name = path.basename(".rb").to_s
         elsif (new_name = @tap.formula_renames[name]) &&
               (new_path = formula_dir/"#{new_name}.rb").file?
+          old_name = name
           path = new_path
           name = new_name
+          new_name = @tap.core_tap? ? name : "#{@tap}/#{name}"
+        elsif (new_tap_name = @tap.tap_migrations[name])
+          new_tap = Tap.fetch new_tap_name
+          new_tap.install unless new_tap.installed?
+          new_tapped_name = "#{new_tap_name}/#{name}"
+          name, path = formula_name_path(new_tapped_name, warn: false)
+          old_name = tapped_name
+          new_name = new_tap.core_tap? ? name : new_tapped_name
+        end
+
+        if warn && old_name && new_name
+          opoo "Use #{new_name} instead of deprecated #{old_name}"
         end
       end
 
-      super name, path
+      [name, path]
     end
 
     def get_formula(spec, alias_path: nil)
diff --git a/Library/Homebrew/os.rb b/Library/Homebrew/os.rb
index b49bbff644..f6fe1eb811 100644
--- a/Library/Homebrew/os.rb
+++ b/Library/Homebrew/os.rb
@@ -13,7 +13,10 @@ module OS
 
   if OS.mac?
     require "os/mac"
-    ISSUES_URL = "https://git.io/brew-troubleshooting".freeze
+    # Don't tell people to report issues on unsupported versions of macOS.
+    if !OS::Mac.prerelease? && !OS::Mac.outdated_release?
+      ISSUES_URL = "https://git.io/brew-troubleshooting".freeze
+    end
     PATH_OPEN = "/usr/bin/open".freeze
     # compatibility
     ::MACOS_FULL_VERSION = OS::Mac.full_version.to_s.freeze
diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index 9f49162d5e..f081d4382b 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -25,6 +25,17 @@ module OS
         end
       end
 
+      def minimum_version
+        case MacOS.version
+        when "10.12" then "8.0"
+        else "2.0"
+        end
+      end
+
+      def minimum_version?
+        version < minimum_version
+      end
+
       def prerelease?
         # TODO: bump to version >= "8.3" after Xcode 8.2 is stable.
         version >= "8.2"
@@ -205,6 +216,17 @@ module OS
         end
       end
 
+      def minimum_version
+        case MacOS.version
+        when "10.12" then "8.0.0"
+        else "4.0.0"
+        end
+      end
+
+      def minimum_version?
+        version < minimum_version
+      end
+
       def outdated?
         if MacOS.version >= :mavericks
           version = Utils.popen_read("#{MAVERICKS_PKG_PATH}/usr/bin/clang --version")
diff --git a/Library/Homebrew/software_spec.rb b/Library/Homebrew/software_spec.rb
index bb432e2dd5..f368c59b54 100644
--- a/Library/Homebrew/software_spec.rb
+++ b/Library/Homebrew/software_spec.rb
@@ -221,7 +221,7 @@ class Bottle
     def initialize(name, version, tag, rebuild)
       @name = name
       @version = version
-      @tag = tag
+      @tag = tag.to_s.gsub(/_or_later$/, "")
       @rebuild = rebuild
     end
 
diff --git a/docs/Formula-Cookbook.md b/docs/Formula-Cookbook.md
index 950b662aeb..6657b97668 100644
--- a/docs/Formula-Cookbook.md
+++ b/docs/Formula-Cookbook.md
@@ -805,7 +805,7 @@ Homebrew wants to maintain a consistent Ruby style across all formulae based on
 
 ### Version detection fails
 
-Homebrew tries to automatically determine the [`version`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#version-class_method) from the [`url`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#url-class_method) in avoid duplication. If the tarball has an unusual name you may need to manually assign the [`version`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#version-class_method).
+Homebrew tries to automatically determine the [`version`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#version-class_method) from the [`url`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#url-class_method) to avoid duplication. If the tarball has an unusual name you may need to manually assign the [`version`](http://www.rubydoc.info/github/Homebrew/brew/master/Formula#version-class_method).
 
 ## Bad Makefiles