diff --git a/lang/admin/cs-CZ.json b/lang/admin/cs-cz.json
similarity index 100%
rename from lang/admin/cs-CZ.json
rename to lang/admin/cs-cz.json
diff --git a/lang/common/cs-CZ.json b/lang/common/cs-cz.json
similarity index 100%
rename from lang/common/cs-CZ.json
rename to lang/common/cs-cz.json
diff --git a/lang/email/cs-CZ.json b/lang/email/cs-cz.json
similarity index 100%
rename from lang/email/cs-CZ.json
rename to lang/email/cs-cz.json
diff --git a/lang/form/cs-CZ.json b/lang/form/cs-cz.json
similarity index 100%
rename from lang/form/cs-CZ.json
rename to lang/form/cs-cz.json
diff --git a/lang/pwreset/cs-CZ.json b/lang/pwreset/cs-cz.json
similarity index 100%
rename from lang/pwreset/cs-CZ.json
rename to lang/pwreset/cs-cz.json
diff --git a/lang/setup/cs-CZ.json b/lang/setup/cs-cz.json
similarity index 100%
rename from lang/setup/cs-CZ.json
rename to lang/setup/cs-cz.json
diff --git a/lang/telegram/cs-CZ.json b/lang/telegram/cs-cz.json
similarity index 100%
rename from lang/telegram/cs-CZ.json
rename to lang/telegram/cs-cz.json