How can I sort the contacts in chronological order of chat?
There is no such option.
how come when I go with spark on history chat, where he asks year, I can not see anything?
Not sure i understand this question. Do you mean you open chat history with one of your contacts and switch view to “one year per page”?
is there a plugin that allows spark to mark as read or to read a chat?
What is the point of marking as read? Spark is not a mail client. Unless i don’t understand what you mean. Or do you mean delivery receipts (seeing that your contact has received your message)? Spark doesn’t have support for that. Don’t understand the second part of that question.