We’ve released WP-Lister for Amazon version 2.8.5, a maintenance update focused on improving the profile conversion system and resolving data handling issues. This release includes 14 fixes that address edge cases discovered as merchants migrate from legacy listing profiles to the new JSON feed format required by Amazon’s Selling Partner API.
Profile Conversion Stability
Version 2.8.5 resolves several issues that affected merchants converting their listing profiles from the legacy format to Amazon’s new product type schema system.
One significant fix prevents the legacy attribute form from appearing on products that have already been converted to use the new JSON feed format. Previously, if you converted a profile and then edited a product, you might see the old attribute interface alongside the new one, creating confusion about which values would actually be submitted to Amazon. The plugin now correctly detects when a product is using a converted profile and displays only the appropriate interface.
An edge case that allowed both legacy and JSON feeds to be generated simultaneously for the same listing has been closed. In certain workflow scenarios, a listing could trigger both feed generation systems, potentially causing conflicts or duplicate submissions. The feed generation logic now ensures only the appropriate feed type is created based on the profile configuration.
We’ve also fixed an issue where feeds were being generated using an old profile even after switching to a new one. This occurred because profile attributes were being evaluated after certain product type checks rather than before. The evaluation order has been corrected to ensure the current profile’s settings are always used.
Data Type and Validation Improvements
Several fixes address data type mismatches and validation errors that could occur during profile conversion and feed generation.
A “Cannot access offset of type string on string” error that occurred during profile conversion has been resolved. This happened when the conversion system expected an array of fields but received a string or empty value instead. The converter now validates data types before attempting to access array elements, preventing these errors and allowing conversion to proceed gracefully even with unexpected input formats.
We’ve added the compatibility_options property to the reindexArrays() method. Amazon’s product type schemas include arrays of compatibility data (like vehicle fitment information), and when these arrays had gaps in their indices, it caused validation errors. The reindexArrays method now properly handles the compatibility_options property, ensuring indices are sequential before submission to Amazon.
Currency and Pricing Fixes
Currency handling in the new JSON feed format has been improved with two related fixes.
First, we’ve resolved an issue where the list_price property was missing its required currency value. Amazon’s JSON feed format requires both price amount and currency code for pricing fields. In some configurations, the currency wasn’t being included with the list price, causing feed validation errors. The price construction logic now ensures currency values are included for all pricing fields.
Second, we’ve added a fallback to use the default schema currency when it’s not explicitly set in the profile. Each Amazon product type has a default currency based on the marketplace, and the plugin now uses this default when a specific currency hasn’t been configured, ensuring prices always include valid currency information.
Sale Price Mapping
The handling of sale prices and their associated date ranges has been improved to prevent validation errors when sale prices are intentionally unmapped.
When you configure a profile and choose not to include sale pricing (by unmapping the sale price field or leaving it empty), the plugin now correctly omits the entire discounted_price structure from the feed. Previously, even with an unmapped sale price, the plugin might include the sale date range, which Amazon would reject as invalid since you can’t have sale dates without a sale price.
This fix checks the profile field configuration for the sale price property before including sale-related data. If the sale price field is set to the unmapped value ([—]) or is empty, neither the sale price nor the sale dates are included in the feed submission.
Item Condition Mapping
Amazon updated their item condition values as part of the move to JSON feeds. Condition values like “UsedLikeNew” became “used_like_new”, “CollectibleGood” became “collectible_good”, and so on. We’ve added a conversion function that automatically maps legacy condition values to the new format, so listings with condition values from older profiles will submit correctly without manual intervention.
FBA Listing Handling
Handling Time (the time it takes to ship an order) must be removed from listings fulfilled by Amazon (FBA). While Seller Fulfilled (FBM) listings require handling time information, including it for FBA listings causes validation errors because Amazon already controls the fulfillment timeline. The feed generation logic now automatically omits handling time for FBA listings while preserving it for FBM listings.
Date Format Standardization
Amazon’s JSON feed format requires dates in YYYY-MM-DD format (ISO 8601). However, various date formats might appear in product data depending on your regional settings or data import methods. We’ve added automatic date format conversion that detects various input formats (MM/DD/YYYY, DD/MM/YYYY, and others) and converts them to the Amazon-required YYYY-MM-DD format before submission. This prevents validation errors caused by date format mismatches.
Custom Size Map Improvements
For merchants using custom size mapping tables (commonly used in apparel categories), we’ve fixed an issue where the table failed to save when field names contained square brackets. Size mapping often requires bracket notation for array-based attributes, and the save handler wasn’t properly escaping these characters. The Custom Size Map table now correctly saves field configurations containing brackets.
Listing Queue Management
We’ve improved how failed listings are handled in the publishing queue. Previously, when a listing failed the canSubmitListing() validation check during automated processing, it would stop the entire queue processing with a return statement. This left the failed listing in the queue and prevented subsequent listings from being processed.
The fix changes this behavior to remove the failed listing from the queue and continue processing remaining listings. Failed listings are still logged and tracked, but they no longer block other listings from being submitted.
How to Update
If you have an active license, you can update through your WordPress admin dashboard. Go to Plugins → Installed Plugins, find WP-Lister for Amazon, and click Update Now. Alternatively, you can download the latest version from your account at wplab.com/account and update manually.
As always, we recommend backing up your site before updating any plugin.
What’s Next
This release continues our focus on ensuring smooth migration to Amazon’s new product type schemas and JSON feed format. As more merchants convert their profiles, we’re identifying and resolving edge cases to ensure the conversion process works reliably across different product categories and configurations. Future updates will continue refining the profile conversion system and addressing feedback from merchants completing the transition.
If you encounter any issues with this release, please contact our support team through wplab.com/support.