diff --git a/lang/admin/da-DK.json b/lang/admin/da-dk.json
similarity index 100%
rename from lang/admin/da-DK.json
rename to lang/admin/da-dk.json
diff --git a/lang/common/da-DK.json b/lang/common/da-dk.json
similarity index 100%
rename from lang/common/da-DK.json
rename to lang/common/da-dk.json
diff --git a/lang/email/da-DK.json b/lang/email/da-dk.json
similarity index 100%
rename from lang/email/da-DK.json
rename to lang/email/da-dk.json
diff --git a/lang/form/da-DK.json b/lang/form/da-dk.json
similarity index 100%
rename from lang/form/da-DK.json
rename to lang/form/da-dk.json
diff --git a/lang/pwreset/da-DK.json b/lang/pwreset/da-dk.json
similarity index 100%
rename from lang/pwreset/da-DK.json
rename to lang/pwreset/da-dk.json
diff --git a/lang/pwreset/de-DE.json b/lang/pwreset/de-de.json
similarity index 100%
rename from lang/pwreset/de-DE.json
rename to lang/pwreset/de-de.json
diff --git a/lang/pwreset/en-GB.json b/lang/pwreset/en-gb.json
similarity index 100%
rename from lang/pwreset/en-GB.json
rename to lang/pwreset/en-gb.json
diff --git a/lang/pwreset/fr-FR.json b/lang/pwreset/fr-fr.json
similarity index 100%
rename from lang/pwreset/fr-FR.json
rename to lang/pwreset/fr-fr.json
diff --git a/lang/pwreset/pt-BR.json b/lang/pwreset/pt-br.json
similarity index 100%
rename from lang/pwreset/pt-BR.json
rename to lang/pwreset/pt-br.json
diff --git a/lang/setup/da-DK.json b/lang/setup/da-dk.json
similarity index 100%
rename from lang/setup/da-DK.json
rename to lang/setup/da-dk.json
diff --git a/lang/telegram/da-DK.json b/lang/telegram/da-dk.json
similarity index 100%
rename from lang/telegram/da-DK.json
rename to lang/telegram/da-dk.json
diff --git a/lang/telegram/de-DE.json b/lang/telegram/de-de.json
similarity index 100%
rename from lang/telegram/de-DE.json
rename to lang/telegram/de-de.json
diff --git a/lang/telegram/fr-FR.json b/lang/telegram/fr-fr.json
similarity index 100%
rename from lang/telegram/fr-FR.json
rename to lang/telegram/fr-fr.json
diff --git a/lang/telegram/nl-NL.json b/lang/telegram/nl-nl.json
similarity index 100%
rename from lang/telegram/nl-NL.json
rename to lang/telegram/nl-nl.json
diff --git a/lang/telegram/pt-BR.json b/lang/telegram/pt-br.json
similarity index 100%
rename from lang/telegram/pt-BR.json
rename to lang/telegram/pt-br.json