during the migration of Jenkins from V 2.89 to V 2.201 I jenkins always tells me,
that there is “Old not readable Data”
“hudson.model.FreeStyleBuild /// Job 12521515 //// CannotResolveClassException: hudson.model.ParametersDefinitionProperty$1”
I found a solution that says it´s fixable by pressing the “Upgrade” Button below it.
Unfortunately there appears no Upgrade-Button. Instead the button “Delete not readable data” appears.
When pressing it. It´s not possible to execute deploy jobs anymore.
Does anyone know how to fix this problem?
Grateful for every help!