I tried to upgrade from 5.1.4 to (the most current) version 5.6.1.
The suggested upgrade path mentioned that I should install versions 5.4.4, 5.5.1 and 5.6.1. So I did. (By the way: the link to version 5.6.1 on CodePlex is incorrect. It links to version 5.6.0.)
When installing version 5.4.4 I got 3 error messages for 2 versions: version 5.3.0 and 5.4.3. I was not able to access my portal anymore. An error message mentioning Telerik showed up. From version 5.3.0 only a beta version is available. Version 5.4.3 can't be downloaded from CodePlex anymore. (At least it is not mentioned under "Other Downloads" at the right side of the page.)
When I first installed version 5.2.3 and then version 5.3.0 no error messages resulted. I think this has to do with the fact that version 5.3.0 does install "Telerik.Web.UI.dll" in the bin directory of your DNN website and version 5.4.4 does not. May be the suggested upgrade path can be adjusted or the update package of version 5.4.4 can be supplemented.
I continued my upgrade with the following error messages. All error message involve the installation of optional modules. Any one got a clue how those can be resolved? (I did a search on the forum for one of the error message, but the suggestions that were mentioned did not solve it or, as far as I could tell, were not applicable.)
The strange thing about the errors below is that the "Taxonomy_01.01.00_Install" resulted in an error in versions 5.4.2 and 5.4.4 but was a success in version 5.5.1. (I performed the upgrade of all mentioned versions twice and both times this applied.)
Using the same trick as above, with the error in version 5.4.3, did not work. While installing version 5.4.2 I got the following 2 error messages:
Installing Optional Modules:
Installing Package File HTML_Community_05.02.00_Install: Success
Installing Package File Messaging_01.01.00_Install: Error!
Installing Package File Taxonomy_01.01.00_Install: Error!
Installing Package File Telerik_05.04.00_Install: Success
And installing version 5.4.4 resulted in the following 3 errors:
Installing Optional Modules:
Installing Package File HTML_Community_05.04.03_Install: Error!
Installing Package File Messaging_01.01.00_Install: Error!
Installing Package File Taxonomy_01.01.00_Install: Error!
Installing Package File Telerik_05.04.00_Install: Success
Upgrading to version 5.5.1 resulted in the following error message:
Installing Optional Modules:
Installing Package File HTML_Community_05.04.03_Install: Success
Installing Package File Messaging_01.01.00_Install: Error!
Installing Package File Taxonomy_01.01.00_Install: Success
Installing Package File Telerik_05.05.00_Install: Success
Upgrading to version 5.6.1 resulted in the following 2 error messages:
Installing Optional Modules:
Installing Package File HTML_Community_05.06.01_Install: Success
Installing Package File Messaging_01.01.00_Install: Error!
Installing Package File Messaging_05.06.01_Install: Error!
Installing Package File Taxonomy_05.06.01_Install: Success
Installing Package File Telerik_05.06.00_Install: Success
In all instances I was able to access my portal. (This was not the case when I installed version 5.4.4 straight away.)