As evidence of this, many courts of appeals have long considered the cross-appeal rule to be a non-jurisdictional "rule of practice," not a statutory command. See, e.g. , id. at 472 ; In re IPR Licensing, Inc. , 942 F.3d 1363, 1370–71 (Fed. Cir. 2019) ; Mendocino Env't Ctr. v. Mendocino County , 192 F.3d 1283, 1298 & nn.27, 28 (9th Cir. 1999) (collecting cases). Additionally, Gunter does not limit its holding to Rule 4(a)(3) ’s 14-day deadline, instead referring to the rule in toto as nonjurisdictional.

Whether the Board improperly relied on new arguments is reviewed de novo. In re IPR Licensing, Inc. , 942 F.3d 1363, 1369 (Fed. Cir. 2019) (citing In re NuVasive, Inc. , 841 F.3d 966, 970 (Fed. Cir. 2016) ).I

See No. 21-1731 J.A. 3341-76. Carucel's reliance on In re IPR Licensing, Inc., 942 F.3d 1363 (Fed. Cir. 2019), where we reversed a Board decision that was based on non-record evidence, is inapposite, as the record of the present appeals contains direct expert support for the Board's findings. Most particularly, substantial evidence supports the Board's conclusions of obviousness.

Id. at 1380-81. Similarly, in In re IPR Licensing, Inc., we reversed a Board decision finding claims unpatentable that relied on draft Universal Mobile Telecommunications System ("UMTS") standards because the petitioner had "not relied on the UMTS standards in its petition" and "pointed to nothing" to support its motivation to combine arguments. 942 F.3d 1363, 1369-70 (Fed. Cir. 2019).

"Whether the Board improperly relied on new arguments is reviewed de novo." Nike, Inc. v. Adidas AG, 955 F.3d 45, 50 (Fed. Cir. 2020) (citing In re IPR Licensing, Inc., 942 F.3d 1363, 1369 (Fed. Cir. 2019)). The IPR provisions of the America Invents Act (AIA) require that a petition identify, "with particularity, each claim challenged, the grounds on which the challenge to each claim is based, and the evidence that supports the grounds for the challenge to each claim."

Because the timeliness of cross-appeals is governed by court-imposed, rather than Congressionally-imposed rules, it is not jurisdictional. See id. at 17 ; see also In re IPR Licensing, Inc. , 942 F.3d 1363, 1372 (Fed. Cir. 2019) . We therefore have jurisdiction to hear the cross-appeal.

We review an agency's compliance with the notice provisions of the APA de novo. See In re IPR Licensing, Inc., 942 F.3d 1363, 1369 (Fed. Cir. 2019) (citing In re NuVasive, Inc., 841 F.3d 966, 970 (Fed. Cir. 2016)).

"Whether the Board improperly relied on new arguments is reviewed de novo." Nike, Inc. v. Adidas AG, 955 F.3d 45, 50 (Fed. Cir. 2020) (citing In re IPR Licensing, Inc., 942 F.3d 1363, 1369 (Fed. Cir. 2019)). The IPR provisions of the America Invents Act (AIA) require that a petition identify, "with particularity, each claim challenged, the grounds on which the challenge to each claim is based, and the evidence that supports the grounds for the challenge to each claim."