According to a post on the tenforums.com the update has been delayed due to "new found problems".
FWIW, I have the 1803 version on my Windows Insider installation.
Dell forum member since 2002
Dell Inspiron 15 - 5577 Laptop
Home Built Desktop PC with ASUS ROG Z170, i7 6700K CPU
Windows 10 64 bit Pro and Windows 10 Insider Program Beta Versions. SSD drives. Cakewalk by BandLab and Studio One 4.1 Recordng Studio Software.
Dell S2719dgf Monitor
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