Overview
Cached Invoices captures a durable snapshot of each invoice in WHMCS. Once cached, that snapshot drives the PDF and client-facing output - so later edits to the customer profile, currency, logo, or PDF template do not silently rewrite what the customer already received.
When it matters
Have you ever had a long-term client with hundreds of invoices ask to switch currency or update contact fields? Without caching, those changes can ripple through historical documents and create accounting headaches, disputes, or inconsistent PDFs.
This addon is built for exactly that class of problem: it stores the data that belonged to the invoice at the time it mattered, and keeps generation consistent whether the PDF is emailed or downloaded from the client area.
Archiving paid invoices
You can go further and automatically create and archive every paid invoice. Even if you later change your PDF template, company logo, or user contact fields, WHMCS continues to produce the same PDF bytes for that invoice - predictable for finance, support, and audits.
Operational fit
The module is designed to be easy to use in daily admin work - caching tools, invoice views, and editing flows are exposed where staff already work. Behaviour is automated so you are not relying on one-off manual exports to stay safe.
Requirements & compatibility
Target stack is WHMCS 8.x and newer with a supported PHP line for your WHMCS version. Heavily customised billing hooks or rare PDF pipelines may need a quick compatibility check - see Requirements on this page or contact us.