diff --git a/Frequently-Asked-Questions.md b/Frequently-Asked-Questions.md
index d5892f4..9a6dd66 100644
--- a/Frequently-Asked-Questions.md
+++ b/Frequently-Asked-Questions.md
@@ -139,7 +139,7 @@ You can build a minified version of PDF.js using the following command:
 
 `gulp minified`
 
-We use Terser to minify the JS files. It is known that other minifiers might break PDF.js code if advanced options are used (see [#710](https://github.com/mozilla/pdf.js/issues/710) or [#2479](https://github.com/mozilla/pdf.js/issues/2479)). It's safe to use minifiers, such as Google Closure Compiler, in whitespace/comments removal mode.
+We use Terser to minify the JS files. It is known that other minifiers might break PDF.js code if advanced options are used (see [#710](https://github.com/mozilla/pdf.js/issues/710) or [#2479](https://github.com/mozilla/pdf.js/issues/2479)). It's safe to use minifiers, such as Google Closure Compiler, in whitespace/comments removal mode. If you are not using `gulp minified`, please note that you *must* configure the minifier to keep original class/function names intact; otherwise the build is not guaranteed to work correctly.
 
 <a name="gh-pages"></a>
 ## Is there a pre-built version PDF.js available?