We're currently upgrading an Umbraco v10 project to v13 LTS. Nested content has been upgraded to Umbraco Block Lists in combination with Umbraco.BlockGrid. All content has been migrated using the uSync.Migrations tool. However, we notice that content pages with Block List items containing the data type 'Umbraco.DropDown.Flexible' are not converting properly, resulting in errors in both the backoffice and frontend. The property value with the data type 'Umbraco.DropDown.Flexible' should have been migrated from the value "simple" to ["simple"]. This migration has been successful for every property except for those within blocks. Does anyone have experience with this issue? Thanks!

Hey Sven - I’ve definitely had to do this. The migration for the drop downs doesn’t affect block data, which is stored as a big JSON blob in the database. Historically when I’ve needed to fix this, I’ve written some Regex to find the property inside the JSON data for the blocks and update it to the new format, then resave the data.

We had a similar issue converting Perplex Content Blocks to Block List. We created a custom migration plan for Usync Migrations where we defined all the required conversions. That helped