error Class 'TijsVerkoyen\CssToInlineStyles\CssToInlineStyles' not found

[RZivaralam]

i have this error ... i extract class CssToInlineStyles into servere without composer

[einpraegsam]

This is not an error because LUXletter needs composer mode (see documentation)

[RZivaralam]

should i install LUXletter with composer? isnt possible without composer ?

[einpraegsam]

Exactly, please check https://github.com/in2code-de/luxletter#technical-requirements

[g-nebel]

The requirement of composer installation in the technical requirements is not sufficient. Typo3 still supports Legacy Installation and your extension is shown in extension manager for Legacy Installation. Please place this requirement on the TYPO3 extension page https://extensions.typo3.org/extension/luxletter