How to? complete backup and restore from a very old v1.3 .4 to latest Node red install

I just dug out my old pi 3 with nodered v1.3.4. (with many flows and installed nodes). Rather than binning the old pi, I intend to start a fresh with the latest pi 3 os and will clean install the latest nodered version.
As I am out of touch with NR for a while and the version is so old, not sure if just copying the jason files will work, what is the best way to migrate to the latest install while retaining all my old flows and installed nodes in the palatte? Advice appreciated.
Thanks,
Ken NZ

Install node red using the bash <curl .. script from the docs. Then copy across the whole .node-red folder, except the node_modules folder and the file package-lock.json, from the old card. In a command window run

cd ~/.node-red
npm install

Which will install the extra nodes. Then start node red.

Great, will try that. Amazing that after so many nodered iterations (versions) that can still do that and the forum is still so helpful! thanks

After starting node-red (assuming that goes ok) then go into Manage Palette in the dropdown menu in node-red and make sure the latest versions of all the nodes are installed.