doc: precisely differentiate framework and tool chain

Issue #2132

doc/getting_started.txt

@@ -31,8 +31,12 @@ For using the entire collection of ported 3rd-party software, the following
 packages should be installed additionally: 'autoconf2.64', 'autogen', 'bison',
 'flex', 'g++', 'git', 'gperf', 'libxml2-utils', 'subversion', and 'xsltproc'.
 
-Furthermore, you will need to install the official Genode toolchain, which
-you can download at [http://genode.org/download/tool-chain].
+Your exploration of Genode starts with obtaining the source code of the
+[https://sourceforge.net/projects/genode/files/latest/download - latest version]
+of the framework. For detailed instructions and alternatives to the
+download from Sourceforge please refer to [https://genode.org/download].
+Furthermore, you will need to install the official Genode tool chain, which
+you can download at [https://genode.org/download/tool-chain].
 
 The Genode build system never touches the source tree but generates object
 files, libraries, and programs in a dedicated build directory. We do not have a
@@ -123,5 +127,5 @@ Please feel welcome to ask your questions and to join the discussions:
 
 :Genode Mailing Lists:
 
-  [http://genode.org/community/mailing-lists]
+  [https://genode.org/community/mailing-lists]
 

doc/tool_chain.txt

@@ -14,7 +14,7 @@ Genode.
 Recommended development platform
 ################################
 
-We use recent [http://www.ubuntu.com/ - Ubuntu] LTS releases on our
+We use recent [https://www.ubuntu.com/ - Ubuntu] LTS releases on our
 development hosts. Hence, Genode should always build without trouble on these
 platforms.
 
@@ -35,8 +35,9 @@ compiled:
   ! sudo tar xPfj genode-toolchain-<version>-<arch>.tar.bz2
   The use of the 'P' option ensures that the tool chain will be installed at
   the correct absolute path '/usr/local/genode-gcc' where the build system
-  expects it to reside by default.
-  [http://sourceforge.net/projects/genode/files/genode-toolchain/ - Download the pre-compiled tool chain...]
+  expects it to reside by default. Please note, Genode OS Framework releases
+  require a Genode tool chain with an equal or next smaller version number.
+  [https://sourceforge.net/projects/genode/files/genode-toolchain/ - Download the pre-compiled tool chain...]
 
 :Compile from source:
   For those of you who prefer compiling the tool chain from source, we provide
@@ -44,8 +45,8 @@ compiled:
   find the tool in Genode's source tree at 'tool/tool_chain'. For usage
   instructions, just start the tool without arguments.
 
-In both cases, the tool chain will be installed to '/usr/local/genode-gcc'. All
-tools are prefixed with 'genode-x86-', 'genode-arm-', or 'genode-riscv-'
+In both cases, the Genode tool chain will be installed to '/usr/local/genode-gcc'.
+All tools are prefixed with 'genode-x86-', 'genode-arm-', or 'genode-riscv-'
 respectively such that it is safe to add the installation directory to our
 'PATH' variable (optional). The Genode tool chain will be used by the Genode
 build system by default. If you desire to use a different tool chain, create a