This page covers the basics of theme updates in Shopify. The benefits, the costs, and what it actually means to "Update your theme."
What is a theme update?
Every theme, over time, gets a small trickle of updates. New Shopify platform features are released, designs get tweaked, bugs get fixed.
You want your store to be running the most up-to-date version of the theme, right? Of course you do!
Is it worth the time and effort to get the latest code up and running? That's a tougher question.
What it involves
Step 1. Install a fresh new copy of the theme, from the theme store
This will be installed as an 'unpublished' version of the theme - it will not affect your live store. You only publish it when you're ready.
Step 2. Set up the new theme settings
Your new theme will be missing some important stuff - like your logo, fonts, colours, home page content. You can set these up again in the theme customizer.
Head down to 'Tip' to find a way to potentially cut down on the time this takes.
Step 3. Set up any apps
Apps that work behind the scenes (like apps to integrate with other platforms, or for shipping) are unlikely to interact with a theme.
Apps that add things into your theme (think Instagram feeds, recommended products, wholesale pricing) will most likely need installing again. Some may automatically install themselves, some may have a button in the app you need to click, you can talk to the app developers to find out more (theme developers won't know).
Step 4. Copy over required theme code changes
You may have hired a developer to add a non-standard feature into your store. For example, tabs on the product page, or extra payment icons into the footer.
It is unlikely that these changes can be moved across to the new theme quickly and easily, it will not be a simple 'copy and paste job'. The code that was altered may work differently now, and there is no mechanism for identifying what changes were made for an individual customisation (it could affect a few lines of code in one file, or hundreds of lines in tens of files - there is no way to know).
You may need to hire that developer to perform those alterations once more - potentially at full cost.
Is it worth it?
The cost is the time you will spend getting the new theme to look and work how you need it to, detecting which apps need installing again, figuring out if they have installed themselves correctly a second time, and redoing any code changes.
The benefit depends on your business - will your customers gain a lot from the update? If you don't notice much of a difference between the versions, it's unlikely your customers will either. But if you want to use a particular new Shopify feature, or just want to make a fresh start, it could be worth it.
It is, of course, up to you!
It is rarely a necessity - we have seen 8 year old themes on stores that are making sales. But if you don't use many apps, and haven't made any code changes, it could be a quick way to bring in the latest features.
You can keep an eye on Shopify's blog to make sure you don't miss any new feature launches!
How to keep your settings
Your colours, fonts, logo, slideshow - anything you set up in the theme customizer - are all stored in a single theme file. This file is located at Config/settings_data.json
This means that if you install a new copy of the theme, you could copy all the saved settings from your old theme into the new one - saving you a fair bit of work!
As we advise when making any theme changes, please make sure to duplicate your current theme first - so you have a backup in case anything goes wrong! (You can do this on your Themes page. Give the copy a name like "Backup - 5-5-2020" so it's easy to find.)
You can open up your current theme in the theme code editor, copy the contents of that file, then open up that file in the new theme, select the contents and paste over them. Click save, and that should preserve your settings.
Note: In some cases, this won't work - usually when settings have changed and the old ones don't line up with the new ones.
Who can help?
As a final comment, if you'd like to use the latest version, but it'll take a lot of work to get everything set up again, then you can hire somebody to take this job off your hands!
You can try TaskHusky - https://goo.gl/ITLrcB
Or look on Shopify's list of developers - https://experts.shopify.com/services/development-and-troubleshooting/add-custom-features-or-code