We have a managed solution which we have been installing for over 2 years. It started in 2011 and is now in 2013.
It is installed on many systems. This issue is seen in only one of them.
(I don't believe the following issue is to do with the upgrade)
There is a custom entity and the form ribbon has 4 custom buttons. These have been given new icons and rules regarding when to display.
On the problem system, into which the new version of the managed solution has been installed, the images are old, one new button has not appeared and the display rules are being ignored.
Although the system has some other solution installed, none of them have the custom entity.
I have tried the force overwrite option.
This has been installed on other systems successfully.
Any ideas on how to correct the problem?