• KOReader version: git-master
• Device: android

Issue

By default wallabag downloads last 30 articles.

When:

• Synchronize remotely deleted files is checked
• and on koreader you already have 30 article (not read) in you wallabag folder,
• and on server you have 50 new ( 30 previously downloaded + 20 new),

on after next sync in Wallabag Koreader dir you will have 30 articles (20 new and 10 already downloaded) and Wallabag plugin will remove 20 previously downloaded not read articles from koreader device.

This seems to be caused by this lines:
https://github.com/koreader/koreader/blob/master/plugins/wallabag.koplugin/main.lua#L637-L639
remote_article_ids is the list of article ids from current download

In this case not being on the current download list doesn't mean it was deleted from server..

Steps to reproduce

Add 30 articles to wallabag server, "download" (sync) them from koreader. Don't read them.
Add 20 more articles to wallabag server. "download" sync them with Koreader. 20 previously downloaded, not read are gone.