G'Day
Yes, a few things, and one of them changes the order in which you do everything.
1. That database copy will go stale. If the 1.5.7c store is still taking orders while you build the 2.2.2 site, everything you do to the new database now (plugin installs, settings, layout) gets thrown away when you copy the live database again at go-live. So either put the old store in maintenance mode and build quickly, or treat this round as a rehearsal: write down every step, then at cutover re-copy the database, re-run the zc_install upgrade, and replay the list. Don't try to merge orders between two databases by hand.
2. Check that the upgrade actually finished. Admin > Tools > Server/Version Info should show a database patch level of 2.2.2, and there should be nothing in logs/ from the install. zc_install upgrades 1.5.7c to 2.2.2 in one pass, so if it says 2.2.2 you're good. Then delete the zc_install folder and set both configure.php files read-only.
3. Character set. The upgrade does NOT convert your tables to utf8mb4. Your copied tables are still utf8 (utf8mb3), while a fresh 2.2.2 configure.php says DB_CHARSET = 'utf8mb4'. That mostly works, but anything with emoji or unusual characters in product text or customer names will break. Either convert the tables to utf8mb4 (phpMyAdmin or a one-off SQL run, on a backup first) or set DB_CHARSET to utf8 in both configure.php files until you do.
4. The old plugins came along in the database, without their files. Every plugin you had on 1.5.7c left configuration keys, admin menu entries, possibly its own tables, and rows in plugin_control. Their files aren't on the new site. Go to Admin > Tools > System Inspection and read the whole page: it lists the admin pages registered to files that don't exist, config groups with no page, and the modules whose files are missing. That's your cleanup list. For each one, run the old plugin's uninstall SQL against the new database, or check whether the 2.x version's installer says it handles a legacy install (lat9's plugins mostly do). Installing on top of stale rows is how you get "duplicate entry" errors and half-installed plugins. Then go to Admin > Modules, remove any payment, shipping, or order total modules that System Inspection flagged, and install the 2.x replacements. Re-run System Inspection until it comes up clean.
5. Template. The database still points at your old template, which probably isn't on the new site, and it wouldn't run on 2.2.2 anyway (2.x changed the language file format and added notifiers a 1.5.7 template doesn't call). Go to Admin > Tools > Template Selection, set responsive_classic or the Bootstrap template, then visit Layout Boxes Controller once so it creates the box rows for that template. Rebuild your look as a thin clone of one of those; don't copy the old template folder over.
6. Things that live in files, not the database. These didn't come across with the database and need copying or redoing:
- Define pages (includes/languages/english/html_includes/<template>/define_*.php): shipping, privacy, conditions, about us, main page text. Copy and re-check them. On PHP 8, unquoted constants in an old define_main_page.php are fatal, not a warning.
- Custom language overrides from includes/languages/english/<template>/: these are the old define() format and must be converted to 2.x lang.*.php arrays, not copied.
- Customized email templates in email/: re-apply your changes to the 2.2.2 versions.
- The download/ folder if you sell downloadable products, media/ if you have music products, plus your .htaccess and robots.txt customizations.
- Time zone: 2.x sets it in includes/extra_configures/set_time_zone.php ($TZ); set it to your Australian time zone.
7. Then look before you install anything. Log in to the admin, click through every menu, and open the storefront with logs/ empty. Fix whatever's broken in core first. Only then start plugins, one at a time, checking logs/ after each.
Once the new site is right, the go-live is just step 1 again: freeze the old store, copy the database, upgrade, replay your list, switch DNS.
