diff --git a/icinga2.spec b/icinga2.spec
index 7f511102a2963db36bbe8cb511a47186a0fc77c0..4b10e47c007ea5c64054368c61346ca80aa71c6e 100644
--- a/icinga2.spec
+++ b/icinga2.spec
@@ -19,7 +19,7 @@
 %define apacheuser apache
 %define apachegroup apache
 
-%if 0%{?el6}%{?amzn}
+%if 0%{?amzn}
 %define use_systemd 0
 %define use_selinux 0
 %if %(uname -m) != "x86_64"
@@ -118,15 +118,10 @@ BuildRequires:  libyajl-devel
 %endif
 BuildRequires:  libedit-devel
 BuildRequires:  ncurses-devel
-%if "%{_vendor}" == "suse" && 0%{?suse_version} < 1210
-BuildRequires:  gcc48-c++
-BuildRequires:  libopenssl1-devel
-BuildRequires:  libstdc++48-devel
-%else
-%if "%{_vendor}" == "redhat" && (0%{?el6} || 0%{?rhel} == 6 || "%{?dist}" == ".el6")
-# Requires devtoolset-7 scl
-%define scl_name devtoolset-7
-%define scl_enable scl enable %{scl_name} --
+%if "%{_vendor}" == "redhat" && (0%{?el7} || 0%{?rhel} == 7 || "%{?dist}" == ".el7")
+  # Requires devtoolset-11 scl
+  %define scl_name devtoolset-11
+  %define scl_enable scl enable %{scl_name} --
 BuildRequires:  %{scl_name}-binutils
 BuildRequires:  %{scl_name}-gcc-c++
 BuildRequires:  %{scl_name}-libstdc++-devel
@@ -135,7 +130,6 @@ BuildRequires:  gcc-c++
 BuildRequires:  libstdc++-devel
 %endif
 BuildRequires:  openssl-devel
-%endif
 BuildRequires:  bison
 BuildRequires:  cmake
 BuildRequires:  flex >= 2.5.35
@@ -170,13 +164,6 @@ BuildRequires:  libboost_test-devel%{?boost_devel_suffix} >= %{boost_min_version
   # default boost devel package
   %define boost_devel_pkg boost-devel
 
-  %if (0%{?el6} || 0%{?rhel} == 6)
-    # Provided by packages.icinga.com
-    %define boost_library icinga-boost169
-    %define boost_version 1.69
-    %define boost_devel_pkg icinga-boost169-devel
-    %define boost_rpath %{_libdir}/%{boost_library}
-  %endif # el6
   %if (0%{?el7} || 0%{?rhel} == 7)
     # Provided by EPEL
     %define boost_library boost169
@@ -413,11 +400,6 @@ CMAKE_OPTS="$CMAKE_OPTS -DICINGA2_WITH_PGSQL=ON"
 CMAKE_OPTS="$CMAKE_OPTS -DICINGA2_WITH_PGSQL=OFF"
 %endif
 
-%if (0%{?el6} || 0%{?rhel} == 6)
-# Explicitly link against rt, because ld doesn't detect it automatically
-CMAKE_OPTS="$CMAKE_OPTS -DCMAKE_EXE_LINKER_FLAGS=-lrt"
-%endif # el6
-
 %if "%{?boost_rpath}" != ""
 CMAKE_OPTS="$CMAKE_OPTS -DCMAKE_INSTALL_RPATH=%{boost_rpath}"
 %endif # boost_rpath
@@ -437,12 +419,6 @@ CMAKE_OPTS="$CMAKE_OPTS
 CMAKE_OPTS="$CMAKE_OPTS -DUSE_SYSTEMD=ON"
 %endif
 
-%if "%{_vendor}" == "suse" && 0%{?suse_version} < 1210
-# from package gcc48-c++
-export CC=gcc-4.8
-export CXX=g++-4.8
-%endif
-
 %if "%{?_buildhost}" != ""
 CMAKE_OPTS="$CMAKE_OPTS -DICINGA2_BUILD_HOST_NAME:STRING=%_buildhost"
 %endif