[ja_JP] Upgrading to the latest release

[shimos]

Original HTML: https://hyperledger-fabric.readthedocs.io/en/release-2.5/upgrade.html
Original Source: https://github.com/hyperledger/fabric/blob/e1e8e2e52aa4fc543360d245fe6554a0eaf81183/docs/source/upgrade.rst

diff --git a/docs/source/upgrade.rst b/docs/source/upgrade.rst
index 227ded5b7..ef3ce4397 100644
--- a/docs/source/upgrade.rst
+++ b/docs/source/upgrade.rst
@@ -12,6 +12,8 @@ high level, a four step process.
    capability levels, where available. Note that some releases will have
    capabilities in all groups while other releases may have few or even no new
    capabilities at all.
+5. If you want to migrate your network by removing the orderer system channel,
+   check out :doc:`create_channel/create_channel_participation`.
 
 For more information about capabilities, check out :doc:`capabilities_concept`.
 
@@ -35,7 +37,7 @@ as there has been for previous releases.
 
 .. note:: It is a best practice to upgrade your SDK to the latest version as a
           part of a general upgrade of your network. While the SDK will always
-          be compatible with equivalent releases of Fabric and lower, it might
+          be compatible with equivalent releases of Fabric and higher, it might
           be necessary to upgrade to the latest SDK to leverage the latest Fabric
           features. Consult the documentation of the Fabric SDK you are using
           for information about how to upgrade.