I'm having two PHP Errors while testing a basic Low Search example. The code can be found here.

The errors shows only while logged in (afaik as super-admin). I'm using EE 2.8.1. Results are working fine.

A PHP Error was encountered

Severity: User Warning

Message: Invalid EE Conditional Variable: {if low_search_category ~ '/\b'.category_id.'\b/'}

Filename: libraries/Functions.php

Line Number: 2640

A PHP Error was encountered

Severity: Warning

Message: Cannot modify header information - headers already sent by (output started at /home/colegios/public_html/system/codeigniter/system/core/Exceptions.php:170)

Filename: core/Common.php

Line Number: 442

Found this at EE bug; but I don't know how to solve it? Should I upgrade to a newer EE2 version? 2.8.1 is stable for me and I want to avoid problems with others addons.

1 Answer 1


To quote the top of the example page in the Low Search docs:

Note: these examples feature conditionals using the Matches Operator introduced in EE 2.9.0. If you’re using an older version of ExpressionEngine, you can use the IN conditionals instead.

So, either use the IN conditionals and continue using EE 2.8.1, or upgrade EE to v2.10.3, which is the latest v2 version at the moment.

  • I will check my others addons to see if they are compatible with latest EE2 version to update. In the meanwhile, tried the IN conditionals and they are working as a charm. Thank you low! Commented Feb 8, 2016 at 5:56

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