Microsoft has released some optional cumulative updates for Windows 10 in 1909, 1903, and 1809. These are the first optional updates since they were discontinued in March due to the COVID-19 pandemic.
Microsoft said last month that July would again bring the optional Windows 10 cumulative updates for Windows 10 1809 (and later) with minor changes. 
Previously, Microsoft had optional updates on the third and fourth week of each month, called "C" and "D" weeks, respectively, and followed the "B" week security update on Patch Tuesday.
The optional update is now available in week C and the company calls it a "Preview" release.
The updated version (δεν περιέχει ενημερώσεις ασφαλείας) “Preview” για τα Windows 10 στις εκδόσεις 1903 και 1909 ανεβάζει το OS number into a 18362.997 and 18363.997, respectively. And the two contain the same updates because the two operating systems share a common kernel system. Updating Windows 10 to version 1809 brings up the build at number 17763.1369.
Υπάρχει μια πολύ μεγάλη λίστα με επιδιορθώσεις σφαλμάτων, συμπεριλαμβανομένων ορισμένων που θα είναι ευπρόσδεκτα από τους χρήστες των Windows 10 στις εκδόσεις 1903 και 1909. Για παράδειγμα ένα γνωστό ζήτημα που εμποδίζει την πρόσβαση στο Διαδίκτυο όταν χρησιμοποιούν συγκεκριμένα μόντεμ wirelessy network (WWAN). This issue has been affecting Windows 10 devices since the update KB4535996 which was released on February 27.
It also encounters an error that prevented Excel from working for some users.
Microsoft reports that it also managed to fix File Explorer to allow users to delete previous terms from the search box, and another problem in File Explorer that prevented it from working when users opened folders with raw images .
