Note: You cannot update from previous Gecko versions to Gecko5. Because Gecko5 is a completely new version and has many user-friendly improvements and is easier to use. If you want to switch from older versions of Gecko to Gecko5 then you most likely have to do a complete set-up again.
Watching tutorial video in here: https://www.youtube.com/watch?v=WGh52LGdKo8&list=PLZSqbv2i8LOD_QjTa-YlD39PsbUG-gJt_&index=6​
​Here are some answers to your questions about Gecko 4 and Gecko 5.​
When our item has a new version, you will receive an updated email from Envato and visit https://themeforest.net/download​
You can download our theme again and extract it to see the theme upload package (like when you used the previous version). Please follow some steps below to understand how to update our items from the old version to the new version. it takes only 1 minute to update.
If you have customized the old version (such as hiring a developer to write new features or customizing our theme) so that the updated version cannot carry these codes, you will need to migrate all the custom code by hand.
Go to Theme actions -> Edit code
Open settings_data.json of theme -> Copy all code.
Go to Theme actions > Edit code.
Paste all code from Old theme to settings_data.json in New theme -> Save.
Result: On new update get all config from old theme
If you are using a different language like French or simple you have to change some English words from default to your so you have to move them from the old theme version to a new theme version.
Go to Edit theme > and open the Locales folder.
Open a language file you are using, for example, if your store uses French so open file fr.json
Open this file from the new theme and paste all content, it will apply your old translation text