I was tasked with patching our DEVELOPMENT environment from SharePoint 2013 SP1 to August 2015 CU. I thought – huh – that is easy! Boy was I in for a big surprise?
When I downloaded the August 2015 CU and started installing, I got an error whose screen shot I don’t have. But the error indicated that the language packs are not updated. First update the language pack and then it will let you update to the CU.
We have language packs installed in the same environment. But what version of language pack do we have? In the Patch Status page if Central Admin, you will see some version numbers for the language packs. But what do these version numbers  mean? We have great blogs posts for determining SharePoint version numbers. But I could not come up with any clue what version numbers to the right of the language packs mean. So I had to take chances. I assumed that we do not have language packs upgraded to SP1. So let me download the SP1 language packs and try to install them. Worst case, it will say we have nothing to install.
So where can I download the SP1 version of language packs? You should get started from here:
Once in this page, select the language packs one by one and download locally. If you have 5 language packs already deployed, you have to download the SP1 version of these language packs 5 times.
Once you are done downloading, copy to SharePoint servers and install one by one and run SP Product Configuration Wizard in all non database SharePoint servers.
Once the language packs are installed, it is time to download the August 2015 CU. When you try to install the binaries, the installation will fail.
From here, you will realize that this is a known issue and it needs to be installed 3 times:
After the usual drill of running the Product Configuration Wizard, you have upgraded to August 2015 CU.
The next natural question is: are there language pack upgrades for August 2015 CU. For this I downloaded August 2015 CU for another language. I binary compared this with the English CU. I did not find any difference in them. Seeing this, I was pretty positive that there is no separate language pack for August 2015 CU.
The patch status page in our farm looks like the following now: