It depends on the version of the test from 23andme. Version 4 (introduced in 2013) tests just four SNPs downstream of I1 - M227, M72, L22, P109. So everybody from any other subclade will just appear as I-M253.
Version 5 of 23andme's chip (from August 2017 onwards) expanded the Y-SNPs that they test below I1 to more than 50. Not very comprehensive, but better than before. The ones that I'm aware of (thanks to a spreadsheet compiled by ArmandoR1b):
[TABLE="width: 623"]
[TR]
[TD]CTS6364/Z2336[/TD]
[TD]A[/TD]
[TD]T[/TD]
[TD]I1a1[/TD]
[/TR]
[TR]
[TD]M227[/TD]
[TD]C[/TD]
[TD]G[/TD]
[TD]I1a1a[/TD]
[/TR]
[TR]
[TD]M227[/TD]
[TD]C[/TD]
[TD]G[/TD]
[TD]I1a1a[/TD]
[/TR]
[TR]
[TD]M227[/TD]
[TD]C[/TD]
[TD]G[/TD]
[TD]I1a1a[/TD]
[/TR]
[TR]
[TD]M72[/TD]
[TD]A[/TD]
[TD]G[/TD]
[TD]I1a1a1[/TD]
[/TR]
[TR]
[TD]M72[/TD]
[TD]A[/TD]
[TD]G[/TD]
[TD]I1a1a1[/TD]
[/TR]
[TR]
[TD]S142/L22[/TD]
[TD]A[/TD]
[TD]C[/TD]
[TD]I1a1b[/TD]
[/TR]
[TR]
[TD]P109[/TD]
[TD]C[/TD]
[TD]T[/TD]
[TD]I1a1b1[/TD]
[/TR]
[TR]
[TD]P109[/TD]
[TD]C[/TD]
[TD]T[/TD]
[TD]I1a1b1[/TD]
[/TR]
[TR]
[TD]Z74[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a1b3[/TD]
[/TR]
[TR]
[TD]L258/S335[/TD]
[TD]G[/TD]
[TD]A[/TD]
[TD]I1a1b3a1[/TD]
[/TR]
[TR]
[TD]L296[/TD]
[TD]G[/TD]
[TD]A[/TD]
[TD]I1a1b3a1a[/TD]
[/TR]
[TR]
[TD]Z719/L813/S436[/TD]
[TD]A[/TD]
[TD]G[/TD]
[TD]I1a1b3b[/TD]
[/TR]
[TR]
[TD]L300/S241[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a1b4[/TD]
[/TR]
[TR]
[TD]Z58/S244[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a2[/TD]
[/TR]
[TR]
[TD]Z59/S246[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a2a[/TD]
[/TR]
[TR]
[TD]Z60/S337[/TD]
[TD]C[/TD]
[TD]G[/TD]
[TD]I1a2a1[/TD]
[/TR]
[TR]
[TD]S439/Z61[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a2a1[/TD]
[/TR]
[TR]
[TD]Z141[/TD]
[TD]A[/TD]
[TD]G[/TD]
[TD]I1a2a1a[/TD]
[/TR]
[TR]
[TD]S440/Z140[/TD]
[TD]G[/TD]
[TD]A[/TD]
[TD]I1a2a1a[/TD]
[/TR]
[TR]
[TD]Z2535/S1953[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a2a1a1[/TD]
[/TR]
[TR]
[TD]S1954/YSC0000261[/TD]
[TD]C[/TD]
[TD]T[/TD]
[TD]I1a2a1a1a[/TD]
[/TR]
[TR]
[TD]S4698/CTS10937/Z2538[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a2a1a1b[/TD]
[/TR]
[TR]
[TD]A196[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a2a1a3[/TD]
[/TR]
[TR]
[TD]Y6900[/TD]
[TD]G[/TD]
[TD]A[/TD]
[TD]I1a2a1a3a[/TD]
[/TR]
[TR]
[TD]Y7140[/TD]
[TD]T[/TD]
[TD]G[/TD]
[TD]I1a2a1a3a1[/TD]
[/TR]
[TR]
[TD]Y7477[/TD]
[TD]G[/TD]
[TD]A[/TD]
[TD]I1a2a1a3a1a[/TD]
[/TR]
[TR]
[TD]Y6885[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a2a1a3a2[/TD]
[/TR]
[TR]
[TD]BY266/Y3657[/TD]
[TD]G[/TD]
[TD]C[/TD]
[TD]I1a2a1b1[/TD]
[/TR]
[TR]
[TD]Y5568[/TD]
[TD]A[/TD]
[TD]C[/TD]
[TD]I1a2a1b1a (unlisted)[/TD]
[/TR]
[TR]
[TD]BY147[/TD]
[TD]A[/TD]
[TD]T[/TD]
[TD]I1a2a1b1a1[/TD]
[/TR]
[TR]
[TD]L573[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a2a1c[/TD]
[/TR]
[TR]
[TD]L1248[/TD]
[TD]A[/TD]
[TD]G[/TD]
[TD]I1a2a1d[/TD]
[/TR]
[TR]
[TD]Z382[/TD]
[TD]G[/TD]
[TD]C[/TD]
[TD]I1a2a2[/TD]
[/TR]
[TR]
[TD]Z2541[/TD]
[TD]G[/TD]
[TD]C[/TD]
[TD]I1a2b1[/TD]
[/TR]
[TR]
[TD]BY151[/TD]
[TD]G[/TD]
[TD]A[/TD]
[TD]I1a3a[/TD]
[/TR]
[TR]
[TD]S2078[/TD]
[TD]C[/TD]
[TD]T[/TD]
[TD]I1a3a1a[/TD]
[/TR]
[TR]
[TD]L1237[/TD]
[TD]A[/TD]
[TD]G[/TD]
[TD]I1a3a1a1a[/TD]
[/TR]
[TR]
[TD]FGC9550/Y6634[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a3a1a1a1[/TD]
[/TR]
[TR]
[TD]S10360[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a3a1a1b[/TD]
[/TR]
[TR]
[TD]S17023[/TD]
[TD]A[/TD]
[TD]G[/TD]
[TD]I1a3a1a1b[/TD]
[/TR]
[TR]
[TD]S15301[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a3a1a1b1[/TD]
[/TR]
[TR]
[TD]Y6228[/TD]
[TD]A[/TD]
[TD]G[/TD]
[TD]I1a3a1a1b1a[/TD]
[/TR]
[TR]
[TD]Y6229[/TD]
[TD]C[/TD]
[TD]T[/TD]
[TD]I1a3a1a1b1a1[/TD]
[/TR]
[TR]
[TD]CTS3848[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a3a1a1c[/TD]
[/TR]
[TR]
[TD]Y6375[/TD]
[TD]C[/TD]
[TD]T[/TD]
[TD]I1a3a1a2[/TD]
[/TR]
[TR]
[TD]BY352[/TD]
[TD]G[/TD]
[TD]C[/TD]
[TD]I1a3a2[/TD]
[/TR]
[TR]
[TD]BY332[/TD]
[TD]C[/TD]
[TD]T[/TD]
[TD]I1a3a2a[/TD]
[/TR]
[TR]
[TD]Y7075/BY354[/TD]
[TD]C[/TD]
[TD]G[/TD]
[TD]I1a3a2a[/TD]
[/TR]
[TR]
[TD]Y7060[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a3a2a1[/TD]
[/TR]
[TR]
[TD]Y7059[/TD]
[TD]G[/TD]
[TD]A[/TD]
[TD]I1a3a2a1[/TD]
[/TR]
[TR]
[TD]BY14[/TD]
[TD]C[/TD]
[TD]T[/TD]
[TD]I1a3a2a1a[/TD]
[/TR]
[TR]
[TD]BY11[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a3a2a1a[/TD]
[/TR]
[TR]
[TD]PH1538/Y14110[/TD]
[TD]G[/TD]
[TD]T[/TD]
[TD]I1a3a2a2[/TD]
[/TR]
[TR]
[TD]Y10994[/TD]
[TD]A[/TD]
[TD]C[/TD]
[TD]I1a3a2b1[/TD]
[/TR]
[TR]
[TD]CTS4279[/TD]
[TD]T[/TD]
[TD]C[/TD]
[TD]I1a3a2c[/TD]
[/TR]
[TR]
[TD]CTS6397[/TD]
[TD]G[/TD]
[TD]C[/TD]
[TD]I1b1[/TD]
[/TR]
[/TABLE]
Some others that appear in other haplogroups as well - [TABLE="width: 623"]
[TR]
[TD="width: 227"]S2169.2/F2642.2[/TD]
[TD="width: 93"]G[/TD]
[TD="width: 94"]A[/TD]
[TD="width: 209"]C[/TD]
[/TR]
[/TABLE]