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Replace your jQuery and Smarty front end step by step

Does your front end depend on jQuery 1.x or 2.x and on Smarty templates that nobody likes to touch? We renew it one area at a time alongside the running system and test after every step. The jQuery project no longer supports the 1.x and 2.x branches (As of 2026-10).

Request a legacy review JavaScript & TypeScript at a glance
  • PHP, Smarty and Slim since 2012
  • Full stack since 2012, front end and back end
  • Reply within one working day
On the left a stack of thin layers full of tangled, curly lines; on the right four clean blocks one above the other, joined by short orange lines

How to recognise a legacy front end

The front end depends on jQuery 1.x or 2.x

Nobody has updated jQuery for years, because plugins that nobody maintains any more depend on it. The jQuery project supports only the current version. The 1.x and 2.x branches receive no more updates, 3.x receives only critical security fixes, and 4.x is current (As of 2026-10, jquery.com (opens in a new window)).

The Smarty templates hold old versions in place

Custom plugins and {php} blocks in the templates turn every update of Smarty and PHP into a risk. Smarty 2 and 3 no longer receive security fixes (As of 2026-10, Smarty project (opens in a new window)). If the PHP upgrade is due as well, read PHP 8 upgrade too.

Every small change takes days

Scripts sit directly in the templates, libraries are loaded twice, and a new feature breaks an old page. Then every change costs more time than it should.

A browser window in which four content blocks are joined by a tangle of thin lines; below it hang three old plugins, one outlined in orange

How we replace the front end: one area at a time, each with a written result

  1. Inventory of the front end

    We record the versions of jQuery and Smarty, plugins, custom Smarty extensions, {php} blocks and scripts in the templates. We add the pages and forms that are used most or carry the greatest risk. You receive the inventory in writing.

  2. Test cases before every change

    For the critical workflows, such as forms, login and search, we write test cases. After every step they show whether everything works as before.

  3. Update where that is enough

    Where an update is enough, we move jQuery and Smarty to maintained versions and replace plugins that nobody maintains any more. We tidy up the templates along the way.

  4. Replace where it pays off

    We rebuild areas that change often, page by page, alongside the old ones. The back end keeps running. If the new front end needs data, we provide it through an API.

  5. Switchover with a way back

    Each area goes live on its own, in a maintenance window agreed with you. Until it runs stably, the old version stays available as the way back.

  6. Handover

    You receive the documentation of the new state and the test cases. The code is in your repository.

Update, replace step by step or rewrite?

Criterion Update jQuery and Smarty Replace the front end step by step Rewrite the front end
Suits you if The application will run for a few more years but rarely changes. The main goal is maintained versions. Some areas change often or are to get new features, and the back end is solid. The back end is being renewed anyway, or the old front end can no longer be updated sensibly.
What it does not solve Messy code in the templates remains; it just runs on maintained versions. For a while old and new pages run side by side, and both need maintenance. Until the switch there are two front ends, and behaviour that nobody wrote down is easily lost.

What we do not promise

  • A new front end does not make an insecure back end secure. We close gaps in the server code as a separate task.
  • The test cases show that appearance and operation stay the same only for the workflows they cover.
  • An update of jQuery and Smarty does not change the design. If the interface is to look new, we plan that as a separate step.
  • We name the effort only once the inventory is available.
A frame holding three boxes for what is part of the work; outside it a dashed box for what is not; the stretch of the frame between them is orange

Our engineers' experience with front ends and the stack behind them

jQuery
Long-running applications, update to maintained versions
New stack
React, Next.js and TypeScript on Node.js, also as a new front end for an existing back end
Operations behind it
Linux, Docker, MySQL and MariaDB

How we start work on your front end

  • Code, credentials and documentation stay with you.
  • An area goes live only after your approval.
  • We also tell you when renewing the front end is not worth it, for example because the application will soon be replaced.

And if someone on our side drops out? We write the documentation on request. The repository is normally with you. We arrange cover on request.

Replacing a front end is part of our service Migration and modernisation.

On the left a sheet with lines of text and a signature line with an orange tick; an arrow points to a server drawn with dashed lines on the right

The first step: Legacy review including the jQuery and Smarty versions

Legacy review

For companies with a system that nobody knows well any more: before an update, before a migration or when changing service provider.

  • Inventory of versions and dependencies
  • Map of application, database, server and email
  • Risk register covering security, support and knowledge
  • Assessment of backups and restores
  • Recommendation “stay, upgrade or migrate” with an options matrix that also covers “move into a container” and “expose as an API”
  • Effort estimate in days

The price covers one system, meaning one application with its database and its server. We price further systems individually.

What the result contains

A written report with inventory, risk register, recommendation and effort estimate. The report is yours.

from €3,800 excl. VAT

Typically 5 working days

Request a legacy review

A case from our work

  • A phone with a QR code, a file split into chunks, three parallel streams to a server with a disk and a gallery grid

    A photo upload app for wedding guests

    Wedding guests scan a QR code, open one secret address and upload photos and videos straight from the phone: no app, no account, no login. Files of up to 5 GB land on the client's own disk, and the couple watches the gallery fill up during the party. One evening, no second chance, and phones from six years back.

Questions about replacing jQuery and Smarty

Is it enough to update jQuery to the current version?

Often that is the first step. The jQuery Migrate plugin reports outdated calls, which we then replace one by one. Most of the effort lies in the plugins: some are no longer maintained and do not work with newer jQuery versions, so we replace them.

The inventory of the front end shows whether the update is enough or whether some areas are better rebuilt.

Will our Smarty templates run under PHP 8?

With Smarty 5, yes: according to the Smarty project it runs with PHP 7.2 to 8.5 (As of 2026-10). The project maintains the latest minor version of Smarty 4 and 5, but not older versions.

When moving to Smarty 5, it is mainly custom plugins, {php} blocks and PHP functions in the templates that need work. We record them in the inventory before we change anything.

Do we have to switch to React or another framework?

No. A framework pays off when a front end is developed further over years and many areas are meant to work without reloading the page. For an application that rarely changes, maintained versions of jQuery and Smarty and tidy templates are often enough.

Once the inventory is available, we decide with you which technology suits your system. We recommend a switch only if it pays off for you.

Do we have to rewrite our system to use a new stack?

No. If the old system is running, we expose its logic as an API and close known security gaps as a one-off step. Its behaviour is meant to stay unchanged, and comparison tests check that. We then build the new part alongside it in the new stack, and it uses that API.

A rewrite is rarely worthwhile. It becomes an option when the framework is no longer maintained, there are no tests and the business rules can be written down. The legacy review clarifies whether that applies to you.

When can you start?

You will receive a first reply within one working day. When we begin work depends on our current workload and on the scope. We give you a binding answer in the intro call. If it is urgent, the 48-hour emergency assessment starts as soon as we have access to the system.

What is your hourly rate?

It depends on scope, engagement model and urgency. Describe your situation briefly and, after a conversation, we will send you an offer. You do not need a budget for that. We quote fixed prices for the entry products.

Which front end needs renewing?

Tell us, as far as you know them, the versions of jQuery, Smarty and PHP and what prompted the question. We reply within one working day and suggest the right first step.

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